Sample supply system of an analytical instrument

Abstract

The sample supply system of the analytical instrument provided by the present invention has one or more valves, a valve assembly that receives an external sample from a sample source, and an external sample reservoir connected to a sample dilution and confluence section via the valve assembly. The valve assembly is configured to selectively allow (i) the flow of the external sample from the sample source to the external sample reservoir and (ii) the flow of the external sample from the external sample reservoir to the sample dilution and confluence section. It includes an external sample reservoir, a first fluid pump that controls the flow of the external sample from the external sample reservoir to the sample dilution and confluence section, a second fluid pump that controls the flow of the diluent to the sample dilution and confluence section and dilutes the external sample to generate a diluted sample, and an analytical sample reservoir that supplies the contained analytical sample to the analyzer of the analytical instrument. The analytical sample reservoir is connected to the sample dilution and confluence section via the valve assembly. The valve assembly is configured to selectively allow (i) the flow of the external sample that bypasses the external sample reservoir along the continuous flow path from the sample source to the analytical sample reservoir and (ii) the flow of the diluted sample from the sample dilution and confluence section to the analytical sample reservoir.

Description

Technical Field

[0001] The present invention relates to a sample supply system for analytical instruments such as inductively coupled plasma (ICP) spectrometers. The present invention also relates to a spectrometer equipped with a sample supply system and an analytical method using such a spectrometer.

[0002] This application claims priority based on Australian Provisional Patent Application No. 2022901996 filed on July 15, 2022, the content of which should be understood to be incorporated herein by reference in part.

Background Art

[0003] Inductively coupled plasma (ICP) spectrometry is an analytical technique used to detect and quantify chemical elements and / or isotope distributions of chemical elements present in a liquid sample. An ICP spectrometer has a plasma torch that receives power from a radio frequency (RF) generator and ionizes argon gas to generate an argon plasma at a temperature of about 7000K. Usually, the liquid sample to be analyzed is atomized to produce an aerosol suitable for contact with the plasma. The plasma evaporates the sample solvent, separates the molecules to be analyzed into their constituent atoms, and those atoms are ionized and / or excited to a high energy state. Subsequently, the elemental composition of the sample is obtained by measuring the emission spectrum of the sample (in an ICP-OES spectrometer) or the mass spectrum of the ionized sample (in an ICP-MS spectrometer).

[0004] ICP spectrometry is widely used as a routine analytical technique in industry. There is a strong incentive to automate the operation of ICP spectrometers to minimize the involvement of human operators and maximize the average speed at which samples can be analyzed by ICP spectrometers to improve the productivity of the instrument.

[0005] An ICP spectrometer generally requires regular calibration curve creation by analyzing standard solutions containing each element to be analyzed with known concentrations to create a calibration curve. This calibration curve will cover the concentration range that includes the concentrations normally expected in the samples to be analyzed and / or the concentrations within the range where the instrument shows a linear response. However, in practice, for one or more elements to be analyzed, it is normal for some samples (e.g., up to 20% maximum) to be outside the range. To perform accurate quantification, it is necessary to dilute the sample so that the out-of-range elements to be analyzed are within the calibration curve range, re-analyze the diluted sample, and calculate the concentration of the analyte in the sample before dilution based on the known dilution level of the diluted sample.

[0006] In diluting samples involving ICP-MS and ICP-OES instruments, various methods have been used so far. Most basically, the sample is diluted to a predetermined dilution level by manual or automatic off-line dilution before analysis. However, systems that cannot be diluted to the required level of the instrument do not offer the advantage of automatically diluting samples found to be out of range, so the impact on the productivity of the instrument is limited. Another system can perform automated off-line sample dilution or on-line sample dilution (with an autosampler) to the required dilution level of the instrument, but there is a risk of carryover because all samples are diluted in the same dilution vial.

[0007] Various in-line sample dilution systems have been proposed so far. Patent Document 1 discloses a sample supply system for an ICP spectrometer that can mix a diluent with the sample stream immediately before sending it to the nebulizer. However, an ICP spectrometer requires that the liquid flow rate to the nebulizer be almost constant and small to maintain plasma stability. When using the sampling configuration of Patent Document 1, the flow to the nebulizer is interrupted during dilution.

[0008] Both Patent Documents 2 and 3 disclose an in-line dilution system having two modules. In the first (sample dilution) module, an external sample is loaded from an autosampler into the first sample loop. The sample then flows from the first sample loop and is diluted in-line by the flow of the diluent, resulting in a diluted sample at the target dilution level. The diluted sample is sent to the second (sample supply) module where it is loaded into the second sample loop. The diluted sample then flows out of the second sample loop and is supplied to an ICP analyzer. According to this configuration, accurate in-line dilution of the sample can be obtained over a wide range of dilution levels, but there is a drawback in that all samples must pass through both modules of the in-line dilution system even when dilution is not required. Sending the sample through the sample dilution module takes a considerable amount of time for analysis. The unfavourable impact on the productivity of the instrument is particularly evident in usage scenarios where only a small number of samples require dilution. Furthermore, the first sample loop must be considerably larger in volume than the second loop in order to enable representative transfer of the undiluted sample for analysis to the second sample loop.

[0009] The above description has been directed to ICP spectrometry, but it will be apparent that similar considerations apply to sample supply systems for a wide range of other analytical instruments, including but not limited to other spectrometers having a plasma source for sample processing, such as microwave plasma spectrometers.

[0010] Therefore, there is a continuing need for a sample supply system for an analytical instrument that at least partially addresses one or more of the above-described drawbacks or provides a useful alternative.

[0011] References to patent documents or other matters shown as prior art in this specification should not be construed as admitting that the document or matter was known at the priority date of all claims or that the information contained in the document or matter was part of common general knowledge.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0013] The present invention provides a sample supply system for an analytical instrument that can operate in two modes. In the first mode, the sample supply system provides a continuous flow path from a sample source (such as an autosampler) to an analytical sample reservoir (typically configured as a sample loop). External samples can thus be directly loaded from the sample source into the analytical sample reservoir and unloaded to the analyzer through a single (sample supply) module without inline dilution. In the second mode, the sample supply system is configured for inline dilution and sample supply through two modules. In the sample dilution module, an external sample is first loaded into an external sample reservoir (which may also be configured as a sample loop if necessary), and then flows from the external sample reservoir and is diluted inline by a controlled flow of a diluent. The diluted sample is sent to the sample supply module, where it flows into the analytical sample reservoir and is then unloaded to the analyzer in the same manner as in the first operating mode. In the first mode, since the sample dilution module is bypassed, undiluted samples can be analyzed quickly. Since the sample dilution module operates only for samples that require dilution, the impact on the productivity of the entire device is minimized. Furthermore, due to the bypass configuration, the external sample held therein is always diluted when sent to the analytical sample reservoir, so the size of the external sample reservoir can be reduced.

[0014] According to a first aspect, the present invention provides a sample supply system for an analytical instrument, comprising a valve assembly including one or more valves for receiving an external sample from a sample source, an external sample reservoir connected to a sample dilution and confluence section via the valve assembly, wherein the valve assembly is configured to selectively allow (i) a flow of the external sample from the sample source to the external sample reservoir and (ii) a flow of the external sample from the external sample reservoir to the sample dilution and confluence section, a first fluid pump for controlling the flow of the external sample from the external sample reservoir to the sample dilution and confluence section, a second fluid pump for controlling the flow of a diluent to the sample dilution and confluence section and diluting the external sample to generate a diluted sample, and an analytical sample reservoir for supplying the contained analytical sample to an analyzer of the analytical instrument, wherein the analytical sample reservoir is connected to the sample dilution and confluence section via the valve assembly, and the valve assembly is configured to selectively allow (i) a flow of the external sample bypassing the external sample reservoir along a continuous flow path from the sample source to the analytical sample reservoir and (ii) a flow of the diluted sample from the sample dilution and confluence section to the analytical sample reservoir.

[0015] In some embodiments, the analytical sample reservoir is configured as an analytical sample loop connected to two ports of a first multiport valve of the valve assembly. When the first multiport valve is in a first valve position, the analytical sample can be loaded into the analytical sample loop, and when the first multiport valve is switched to a second valve position, the analytical sample can be supplied from the analytical sample loop to the analyzer. The sample supply system can further comprise a third fluid pump for flowing a first carrier fluid to the first multiport valve. The first multiport valve is configured to flow the first carrier fluid directly to the analyzer through the first multiport valve when the first multiport valve is in the first valve position, and to divert the first carrier fluid through the analytical sample loop and supply the analytical sample from the analytical sample loop to the analyzer when the first multiport valve is switched to the second valve position. Optionally, the sample supply system can further comprise a bubble injector for injecting bubbles for separating the first carrier fluid from the analytical sample when the first carrier fluid flows through the analytical sample loop.

[0016] In some embodiments, the sample supply system is preferably disposed downstream of the analytical sample reservoir and further includes a fourth fluid pump or a vacuum source for flowing an external sample along a continuous flow path from the sample source to the analytical sample reservoir. The sample supply system can bypass the fourth fluid pump or the vacuum source when the diluted sample flows from the sample dilution junction to the analytical sample reservoir. The valve assembly can be configured to allow the fourth fluid pump or the vacuum source to flow an external sample from the sample source to the external sample reservoir.

[0017] In some embodiments, the valve assembly can be configured to allow the first fluid pump to flow an external sample from the sample source to the external sample reservoir.

[0018] In some embodiments, the valve assembly includes a second multiport valve connected to the analytical sample reservoir, and the second multiport valve is switchable between at least a first valve position allowing the flow of the external sample along the continuous flow path from the sample source to the analytical sample reservoir and a second valve position allowing the flow of the diluted sample from the sample dilution junction to the analytical sample reservoir. The second multiport valve can be switched to a third valve position allowing the flow of the external sample from the sample source to the external sample reservoir. When the second multiport valve is switched to the second valve position, the second fluid pump can control the flow of the diluent to the sample dilution junction passing through the second multiport valve. The sample dilution junction may be inside the second multiport valve.

[0019] In some embodiments, the external sample reservoir is configured as an external sample loop connected to the valve of the valve assembly.

[0020] In some embodiments, the external sample reservoir is configured as an external sample loop connected to two ports of the third multiport valve of the valve assembly. The external sample can be loaded into the external sample loop when the third multiport valve is in the second valve position, and the external sample can be supplied from the external sample loop to the sample dilution confluence section when the third multiport valve is switched to the first valve position. The valve assembly can be configured to allow the first fluid pump to flow the second carrier fluid through the external sample loop and to flow the external sample from the external sample loop to the sample dilution confluence section when the third multiport valve is switched to the first valve position. The sample supply system can be configured to introduce bubbles that separate the second carrier fluid and the external sample when the second carrier fluid flows through the external sample loop. The valve assembly can be configured to allow the second fluid pump to flow the diluent through the third multiport valve to the sample dilution confluence section when the third multiport valve is in the first valve position. The sample dilution confluence section may be inside the third multiport valve. The valve assembly can be configured to allow the flow of the external sample along a continuous flow path from the sample source through the third multiport valve to the analytical sample reservoir when the third multiport valve is in the first valve position.

[0021] In some embodiments, the first fluid pump and the second fluid pump are configured to flow the external sample and the diluent at a relative flow rate (v / v) in the range of 10:1 to 1:1000, for example, in the range of 1:1 to 1:250.

[0022] In some embodiments, the first fluid pump and the second fluid pump are configured to flow the external sample and the diluent at a total flow rate of 2 ml / min to 20 ml / min, for example, 5 ml / min to 15 ml / min, for example, 10 ml / min.

[0023] In some embodiments, the volume of the external sample reservoir is less than 20% larger than the volume of the analytical sample reservoir. In some embodiments, the volume of the external sample reservoir is less than or equal to the volume of the analytical sample reservoir.

[0024] In some embodiments, the sample supply system further comprises a sample source, and the sample source is connected to an external sample reservoir and an analytical sample reservoir via a valve assembly. The sample source can be selected from the group consisting of an autosampler and an automated interface for sampling a process fluid.

[0025] According to a second aspect, the present invention provides a spectrometer comprising a sample supply system according to any of the embodiments of the first aspect and an analytical device.

[0026] In some embodiments, the analytical device has a plasma source.

[0027] In some embodiments, the spectrometer is an ICP-OES spectrometer and / or an ICP-MS spectrometer.

[0028] In some embodiments, the spectrometer further comprises a computing device for controlling the sample supply system to supply an external sample for spectroscopic analysis according to either method (a) or method (b). Method (a) includes (i) flowing an external sample from the sample source along a continuous flow path to the analytical sample reservoir without dilution, and (ii) subsequently supplying the external sample from the analytical sample reservoir to the analytical device for spectroscopic analysis. Method (b) includes (i) flowing an external sample from the sample source to the external sample reservoir, (ii) subsequently flowing the external sample from the external sample reservoir to a sample dilution junction, (iii) simultaneously flowing a diluent to the sample dilution junction to dilute the external sample and generate a diluted sample, (iv) flowing the diluted sample from the sample dilution junction to the analytical sample reservoir, and (v) subsequently supplying the diluted sample from the analytical sample reservoir to the analytical device for spectroscopic analysis.

[0029] In some embodiments, the computing device supplies a first external sample for spectroscopic analysis according to method (a), determines a target dilution rate of the first external sample based on the spectroscopic analysis of the first external sample, and supplies a diluted sample containing the first external sample and a diluent for spectroscopic analysis according to method (b), wherein the first fluid pump and the second fluid pump are controlled such that the first external sample and the diluent flow at a relative flow rate suitable for achieving the target dilution rate in the diluted sample.

[0030] According to a third aspect, the present invention provides a method of analysis using a spectrometer according to any embodiment of the second aspect, the method comprising providing one or more external samples to a sample source for analysis; and analyzing at least a first sample of the one or more external samples by a first analysis technique without dilution of the first sample, the first analysis technique comprising: (i) flowing the first sample along a continuous flow path from the sample source to an analytical sample reservoir; and (ii) subsequently supplying the first sample from the analytical sample reservoir to an analytical device for spectroscopic analysis.

[0031] In some embodiments, the method comprises analyzing at least a first sample or a second sample of the one or more external samples by a second analysis technique with in-line dilution of the first sample or the second sample, the second analysis technique comprising: (i) flowing the first sample or the second sample from the sample source to an external sample reservoir; (ii) subsequently flowing the first sample or the second sample from the external sample reservoir to a sample dilution junction; (iii) simultaneously flowing a diluent to the sample dilution junction to dilute the first sample or the second sample to produce a diluted sample; (iv) flowing the diluted sample from the sample dilution junction to an analytical sample reservoir; and (v) subsequently supplying the diluted sample from the analytical sample reservoir to an analytical device for spectroscopic analysis.

[0032] In some such embodiments, the method includes determining a target dilution rate of a first sample based on spectroscopic analysis of the first sample obtained by a first analysis technique, and analyzing the first sample by a second analysis technique, wherein a first fluid pump and a second fluid pump of a sample supply system are controlled such that the first sample and a diluent flow at relative flow rates suitable for achieving the target dilution rate in the diluted sample.

[0033] In other such embodiments, the method includes providing, for analysis, a calibration sample to a sample source, the calibration sample having one or more analytes of known concentration, analyzing the calibration sample by a first analysis technique, supplying the calibration sample to an analytical device for spectroscopic analysis, analyzing the calibration sample one or more times by a second analysis technique, and supplying, for spectroscopic analysis, one or more diluted calibration samples having one or more analytes of known concentration to the analytical device.

[0034] In some embodiments, the method includes providing a plurality of external samples to a sample source for analysis, analyzing the plurality of external samples by a first analysis technique, identifying, based on spectroscopic analysis of the plurality of external samples, an out-of-range sample having an analyte concentration above a predetermined maximum concentration among the plurality of external samples, and, if identified, analyzing the out-of-range sample by a second analysis technique with inline dilution of the out-of-range sample, the second analysis technique including (i) flowing the out-of-range sample from the sample source to an external sample reservoir, (ii) subsequently flowing the out-of-range sample from the external sample reservoir to a sample dilution junction, (iii) simultaneously flowing a diluent to the sample dilution junction to dilute the out-of-range sample to produce a diluted sample having an analyte concentration below the predetermined maximum concentration, (iv) flowing the diluted sample from the sample dilution junction to an analysis sample reservoir, and (v) subsequently supplying the diluted sample from the analysis sample reservoir to an analytical device for spectroscopic analysis.

[0035] In this specification (including the claims), when the terms "include, comprise (comprise, comprises, and comprising)" are used, these terms should be construed as not excluding the existence of one or more other features, elements, steps, or components, or groups thereof, that specify the recited features, elements, steps, or components.

[0036] In this specification, terms such as "first," "second," "third," etc., related to various features of the disclosed apparatus are assigned as necessary, and are merely intended to distinguish between two or more such features that the apparatus may have in various embodiments. These terms do not themselves indicate any particular direction or order. Further, it should be understood that the presence of the "first" feature does not mean the presence of the "second" feature, the presence of the "second" feature does not mean the presence of the "first" feature, etc.

[0037] Further aspects of the present invention will be described below in the detailed description of the invention.

[0038] Embodiments of the present invention will be described below merely as examples with reference to the accompanying drawings in this specification.

Brief Description of the Drawings

[0039]

Figure 1

Figure 2

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Figure 11

Embodiments for Carrying Out the Invention

[0040] The present invention relates to a sample supply system for an analytical instrument. The sample supply system has one or more valves and includes a valve assembly that receives an external sample from a sample source such as an autosampler. The sample supply system is connected to a sample dilution and confluence section via the valve assembly and has an external sample reservoir (for example, in the form of a sample loop) that is connected to the sample source during use. The valve assembly can be configured to selectively allow (i) the flow of an external sample from the sample source to the external sample reservoir and (ii) the flow of the external sample from the external sample reservoir to the sample dilution and confluence section. A representative aliquot of the external sample can be sequentially transferred into and then out of the external sample reservoir. The sample supply system has a first fluid pump that controls the flow of the external sample from the external sample reservoir to the sample dilution and confluence section, and a second fluid pump that controls the flow of a diluent to the sample dilution and confluence section, thereby diluting the external sample to generate a diluted sample.

[0041] The sample supply system further has an analytical sample reservoir (for example, in the form of a sample loop) that supplies an analytical sample to an analyzer of the analytical instrument. The analytical sample reservoir is connected to the sample dilution and confluence section via the valve assembly and is connected to the sample source during use. The valve assembly can be configured to selectively allow (i) the flow of an external sample along a continuous flow path from the sample source to the analytical sample reservoir, thereby bypassing the external sample reservoir, and (ii) the flow of the diluted sample from the sample dilution and confluence section to the analytical sample reservoir.

[0042] <Valve assembly> The sample supply system comprises a valve assembly having two or more valves, such as one or more valves, for example, two or three valves. In some embodiments, one or more of the valves are multiport switching valves that can be switched to any of at least two distinct valve positions (e.g., two or three valve positions) to change the internal flow channels of the valve between the ports of the valve. A suitable multiport valve can be a rotary switching valve having at least four ports, generally at least five, six or seven ports. In some exemplary embodiments, the valve assembly includes one or more seven-port rotary valves, such as, for example, the Cheminert® switching valve provided by Valco Instruments Company Inc. (VICI). The valve assembly may include one or more other types of valves, such as solenoid valves or shut-off valves. As will be understood by those skilled in the art, valve assemblies that conform to the principles disclosed herein can include a wide range of valve types and configurations.

[0043] The valve assembly receives an external sample from a sample source, such as an autosampler, and supplies the sample, either undiluted or diluted as required, for analysis in an analytical instrument (e.g., an analytical instrument having a plasma source such as an ICP spectrometer) via a nebulizer if necessary. The valve assembly may include various fluid flow lines including: (i) a sample source line connected to the valves of the valve assembly for receiving an external sample from the sample source; (ii) one or more sample transfer lines each connected to two valves of the valve assembly for transferring a sample or other fluid between the valves; and (iii) a sample supply line connected to the valves of the valve assembly for supplying the analysis sample to the analytical instrument. These lines, and the internal flow channels between the ports inside the valves, are generally narrow (e.g., having an inner diameter of 1 mm or 2 mm) such that fluid can flow through the valve assembly in a substantially plug flow mode.

[0044] As used herein, two components being "connected" means that these components are connected so as to enable fluid flow therebetween, either directly or through other components, provided that the valve assembly is configured to permit such flow.

[0045] <External sample reservoir> The sample supply system includes an external sample reservoir connected to the sample dilution junction via a valve assembly. The valve assembly can be configured to selectively permit either (i) the flow of an external sample from a sample source to the external sample reservoir (i.e., loading), or (ii) the flow of the external sample held in the external sample reservoir to the sample dilution junction (i.e., unloading).

[0046] As used herein, the external sample reservoir receives and holds a representative aliquot of the external sample in a volume sufficient to be transferred, with subsequent dilution to the required dilution level, for analysis. Preferably, the external sample reservoir has a narrow fluid line (e.g., with an inner diameter of 1 mm or 2 mm) of sufficient length to provide the required holding capacity and allows fluid to flow into and out of the external sample reservoir in a substantially plug flow mode.

[0047] In some embodiments, the external sample reservoir is configured as a sample loop ("external sample loop") connected to two ports of a multiport valve of the valve assembly. In this case, the external sample can be loaded into the external sample loop when the multiport valve is in a certain valve position, and can be supplied from the external sample loop to the sample dilution junction when the multiport valve is switched to another valve position. The flow of the external sample into the external sample loop may preferably be driven by a fluid pump, such as a high flow piston pump or a vacuum pump, or a vacuum source, provided downstream of the valve assembly in the flow path to a drain (sample discharge port).

[0048] Other configurations of the external sample reservoir are also envisioned. For example, the external sample reservoir may have a line connected to only one end of the multi-port valve of the valve assembly. Optionally, the other end may be connected to a reversible fluid pump. In this case, the reversible fluid pump can be used to load an external sample into the external sample reservoir and discharge it from the external sample reservoir.

[0049] <The first fluid pump, the second fluid pump, and the sample dilution confluence section> The sample supply system has a first fluid pump and a second fluid pump for controlling the degree of dilution of an external sample when dilution is required. The first fluid pump controls the flow of the external sample from the external sample reservoir to the sample dilution confluence section, and the second fluid pump controls the flow of the diluent from the diluent source to the sample dilution confluence section. The two independently controllable flows merge at the sample dilution confluence section, whereby the external sample is diluted and a diluted sample is produced.

[0050] In some embodiments, the first fluid pump flows a carrier fluid through the external sample reservoir, thereby flowing the external sample from the external sample reservoir to the sample dilution confluence section ("flushing"). The use of the carrier fluid provides the advantage that the external sample does not come into contact with the first fluid pump. Optionally, the system can introduce air bubbles to separate the carrier fluid and the external sample and avoid or limit the mixing of the two fluids within an acceptable range.

[0051] In some embodiments, the second fluid pump is disposed upstream of the sample dilution junction, and acts directly on the diluent when the diluent flows from a diluent source (e.g., a tank or the internal space of the pump) through the second fluid pump to the sample dilution junction. However, it is not necessary for the second fluid pump to act directly on the diluent. For example, the second fluid pump may be disposed downstream of the sample dilution junction, preferably downstream of the valve assembly in the flow path to the drain (sample discharge port). The second fluid pump acts directly on the diluted sample or another fluid further downstream in the flow path, thereby accurately controlling the flow of the overall combination of the external sample and the diluent. The first fluid pump accurately controls only the flow rate of the external sample. The diluent is drawn into the sample dilution junction at the required flow rate, i.e., as the difference between the flow rate of the first fluid pump and the flow rate of the second fluid pump. In this way, the second fluid pump indirectly controls the flow of the diluent to the sample dilution junction.

[0052] It will also be understood that the first fluid pump may be disposed downstream to accurately control the flow of the overall combination of the external sample and the diluent, and the second fluid pump may accurately control only the flow of the diluent. The first fluid pump indirectly controls the flow of the external sample to the sample dilution junction. In either case, the sample supply system needs to be appropriately configured such that the initial transfer of the external sample from the sample source to the sample reservoir is possible before subsequent dilution steps in which the first and second fluid pumps operate as described herein.

[0053] The first fluid pump and the second fluid pump may preferably be a syringe pump or other positive displacement pump, such as a piston pump, that can accurately control the fluid flow rate within the required range. Alternatively, the pump may be used in combination with a flow meter to accurately control the flow. In some embodiments, the first fluid pump and the second fluid pump are configured to flow an external sample and a diluent at a relative flow rate (v / v) within the range of 10:1 to 1:1000, such as within the range of 1:1 to 1:400, such as within the range of 1:1 to 1:250. In some embodiments, the first fluid pump and the second fluid pump are configured to flow an external sample and a diluent at a combined flow rate of 2 ml / min to 20 ml / min, preferably 5 ml / min to 15 ml / min, such as about 10 ml / min.

[0054] The controlled flow of the external sample and the diluent merges at the sample dilution confluence section, whereby the external sample is diluted to produce a diluted sample having the required dilution level. The sample dilution confluence section may be, if necessary, inside the multi-port valve of the valve assembly, for example, at the port of the valve where two internal flow channels passing through the valve merge. However, any sample dilution confluence section that can merge and subsequently mix the two flows is included.

[0055] <Analytical sample reservoir> The sample supply system has an analytical sample reservoir for supplying an analytical sample to an analyzer. The analytical sample reservoir is connected to the sample dilution confluence section via a valve assembly and is connected to a sample source at least during use. The valve assembly can selectively allow either (i) the flow of the external sample that bypasses the external sample reservoir along the continuous flow path from the sample source to the analytical sample reservoir (i.e., loading the undiluted analytical sample), or (ii) the flow of the diluted sample from the sample dilution confluence section to the analytical sample reservoir (i.e., loading the diluted analytical sample).

[0056] In this specification, the analytical sample reservoir receives and holds a representative aliquot of the diluted or undiluted sample in an amount sufficient for subsequent transfer to an analyzer (e.g., via a nebulizer) for spectroscopic analysis. Preferably, the analytical sample reservoir has a narrow fluid line (e.g., with an inner diameter of 1 mm or 2 mm) of sufficient length to provide the necessary holding volume, allowing fluid to flow into and out of the analytical sample reservoir in substantially plug flow mode.

[0057] The flow of the external sample along the continuous flow path from the sample source to the analytical sample reservoir may preferably be driven by a fluid pump, such as a high-flow piston pump or a vacuum pump, or a vacuum source, disposed downstream of the analytical sample reservoir in the flow path to the drain (sample outlet). The flow of the diluted sample from the sample dilution junction to the analytical sample reservoir is driven by a first fluid pump and a second fluid pump.

[0058] In some embodiments, the analytical sample reservoir is configured as a sample loop ("analytical sample loop") connected to two ports of a multi-port valve of a valve assembly. In this case, the analytical sample can be loaded into the analytical sample loop when the multi-port valve is in a certain valve position, and can be supplied from the analytical sample loop to the analytical device when the multi-port valve is switched to another valve position. A fluid pump may be provided as needed to directly flow the carrier fluid through the multi-port valve to the analytical device when the multi-port valve is in the first valve position, and to bypass the carrier fluid through the analytical sample loop when the multi-port valve is switched to the second valve position. Thereby, the analytical sample is supplied ( "pushed") from the analytical sample loop to the analytical device without interrupting the continuous flow of liquid to the analyzer. Optionally, the system may have a bubble injector for injecting gas bubbles to separate the carrier fluid from the analytical sample.

[0059] Other configurations of the analytical sample reservoir are also envisioned. For example, the analytical sample reservoir may have a line connected to only one end of the multi-port valve of the valve assembly. The other end may be connected to a reversible fluid pump. In this case, the reversible fluid pump can be used to load the analytical sample into the analytical sample reservoir and discharge it from the analytical sample reservoir.

[0060] A feature of the sample supply system disclosed herein is that the external sample stored in the external sample reservoir is always diluted when sent to the analytical sample reservoir during normal operation. Therefore, the external sample reservoir can have a smaller volume (sample holding capacity) compared to the case where it is required to send a representative external sample to the analytical sample reservoir without dilution. As an example, the external sample reservoir and the analytical sample reservoir can be of approximately equal size. This provides a sufficient amount of diluted sample to wash the analytical sample loop and leave a representative aliquot of the diluted sample in the analytical sample loop when the minimum dilution ratio is 1:1. As an advantage, the analytical sample system requires less sample compared to an equivalent sample supply system that includes an analytical sample reservoir but does not have an in-line dilution function.

[0061] <Sample source> The sample supply system may have a sample source for providing one or more external samples during analysis. As used herein, an external sample is a sample provided outside and upstream of the sample supply system. The sample source may be permanently connected to the valve assembly through a sample source line or may be removably connected. During use, the sample source is placed upstream of all the valves of the valve assembly. This is specifically not an in-line sample loop connected to the valves of the valve assembly.

[0062] The sample source may be an autosampler that sequentially samples a plurality of separate external samples (e.g., in a sample vial) provided for analysis. Optionally, such an autosampler may also include a rinse fluid source that can be used to clean the valve assembly and any sample reservoir in various operating modes.

[0063] Incidentally, it will be understood that the sample source may in principle be any container or instrument capable of providing an external sample for analysis via a valve assembly. For example, an analytical instrument such as an ICP spectrometer can be integrated into an industrial process for the purpose of online monitoring, and in such a case the sample source may take the form of an automated interface having one or more pumps, selection valves, etc., and sampling the process fluid. The automated interface may even perform on the primary sample one or more sample preparation processes including (but not limited to) digestion and reagent addition, thereby providing a pre-treated external sample for transfer to the valve assembly of the sample supply system.

[0064] <Exemplary Embodiment> Figures 1-5 show a sample supply system 100 according to an embodiment of the present invention. The system 100 includes a valve assembly 102 having a first multiport valve 104, a second multiport valve 106, and a third multiport valve 108. Each multiport valve is switchable between a first valve position and a second valve position, and three flow channels inside the valve provide different sets of connections between two ports in the valve. The multiport valves 104, 106, and 108 may each be 7-port rotary valves. The second multiport valve 106 does not utilize all seven ports, and the unused ports 1 and 7 are simply blocked. Alternatively, the valve 106 may be a custom 5-port valve.

[0065] The first multiport valve 104 is connected to an analytical sample loop 110 connected to ports 1 and 4 of the valve 104. The analytical sample loop 110 has a coil of a small-diameter tube (e.g., with an inner diameter of 1 mm or 2 mm) having a volume sufficient to hold an analytical sample (depending on the application, e.g., 0.25 ml to 4 ml, e.g., 1 ml to 2 ml) for subsequent analysis in the analytical device 124. The valve 104 is also connected to the valve 106 through a load line 112 connected to port 6 of the valve 104 and port 4 of the second multiport valve 106. When the first multiport valve 104 is in the first valve position as shown in FIG. 1, the undiluted or diluted sample to be analyzed can be loaded into the analytical sample loop 110 by flowing from the load line 112 through the analytical sample loop 110, out of port 5 of the valve 104, and into the drain line 113. This flow continues at least until the analytical sample loop 110 holds a representative sample.

[0066] The system 100 further includes a third fluid pump 114 that flows a first carrier fluid 116 (also known as a rinse fluid) through a carrier fluid line 118 connected to port 3 of the first multiport valve 104 to the valve 104. The third fluid pump 114 may be a peristaltic pump that supplies a carrier fluid at a substantially constant flow rate (depending on the application, e.g., 0.3 ml / min for ICP-MS and 1 ml / min for ICP-OES) during use. When the first multiport valve 104 is in the first valve position as shown in FIG. 1, the pump 114 flows the first carrier fluid 116 directly through the valve 104, out of port 2, and then proceeds through the sample supply line 120 to the nebulizer 122. The atomized microdroplets can then be classified in a spray chamber (spray chamber, not shown) and sent to the analytical device 124 (e.g., an ICP-OES analyzer or an ICP-MS analyzer).

[0067] When an analytical sample representative of the undiluted or diluted sample to be analyzed is loaded into the analytical sample loop 110, the analytical sample is then supplied to the nebulizer 122 through the sample supply line 120 by switching the first multi-port valve 104 to the second valve position as shown in FIG. 2. The flow of the first carrier fluid 116 bypasses through the analytical sample loop 110, pushes the analytical sample from the valve 104 through the sample supply line 120 to the nebulizer 122, where the analytical sample is atomized and subsequently analyzed by the analytical device 124.

[0068] The system 100 may optionally have a bubble injector 126 that injects gas bubbles (e.g., pressurized argon) into the carrier fluid line 118 immediately before the connection to port 3 of the valve 104. Bubbles are injected when the first multi-port valve 104 is switched to the second valve position to bypass the first carrier fluid 116 through the analytical sample loop 110. And the bubbles physically separate the first carrier fluid 116 from the analytical sample when the carrier fluid flows through the analytical sample loop and pushes the analytical sample to the nebulizer 122. Thereby, unwanted dilution of the analytical sample when it is sent to the nebulizer 122 is prevented or reduced.

[0069] The system 100 may further include a fifth fluid pump 128, which can also be a peristaltic pump here if necessary, for flowing the internal standard solution 130 into the sample supply line 120. Typically, the pump 114 and the pump 128 are two channels of a single peristaltic pump unit, and advantageously ensure a consistent ratio of the flow of the internal standard solution 30 and the flow of the first carrier fluid 116. The flow of the internal standard solution 130 can be directed to enter port 7 and exit port 2 through the valve 104 regardless of whether the first multi-port valve 104 is in the first valve position or the second valve position as shown in FIGS. 1 and 2. In this way, the internal standard solution mixes with the flow of the first carrier fluid 116 and / or the analytical sample before reaching the nebulizer 122. Alternatively, the flow of the internal standard solution 130 may be added to the sample supply line 120 downstream of the valve 104.

[0070] Despite the discontinuous supply of the analysis sample from the analysis sample loop 110, system 100 supplies a substantially continuous flow of liquid to the nebulizer 122, which is determined by the total flow rate of the third fluid pump 114 and the fifth fluid pump 128 (if present). Such a configuration is particularly desirable when the analyzer 124 has a plasma source for sample processing, because a constant flow of liquid helps maintain the stability of the plasma flame.

[0071] As shown in FIG. 1, system 100 is configured such that an undiluted or diluted sample to be analyzed is loaded into the analysis sample loop 110 via port 1 and exits port 1 for supply for analysis ("last in, first out"). Alternatively, the load line 112 may be connected to port 5 of the valve 104 and the drain line 113 may be connected to port 6, such that the fluid to be analyzed is loaded into the analysis sample loop 110 via port 4 while still exiting port 1 for supply for analysis ("first in, first out").

[0072] The second multi-port valve 106 is connected to the valve 108 through a sample transfer line 132 that is connected to port 5 of the valve 106 and port 6 of the third multi-port valve 108. The third multi-port valve 108 is connected to the sample source 134 through a sample source line 136 that is connected to port 5 of the valve 108. The sample source 134 may be an autosampler that provides one or more external samples for analysis and sequentially samples a plurality of separate external samples (e.g., in a sample vial) provided for analysis. However, the sample source 134 is not so limited and may be, for example, an automated interface for periodic online monitoring of a process fluid, such as a process stream in an industrial process or a food process.

[0073] As shown in FIG. 1, the first multiport valve 104, the second multiport valve 106, and the third multiport valve 108 are each in the first valve position. The valve assembly 102 allows the flow of external samples along a continuous flow path from the sample source 134 to the analysis sample loop 110 (through the sample source line 136, the valve 108, the sample transfer line 132, the valve 106, the load line 112, and the valve 104).

[0074] System 100 has a fourth fluid pump 142 located downstream of the first multiport valve 104 and forming part of the flow path between the valve 104 and the drain 140 when the bypass valve 138 is in the first setting. The fourth fluid pump 142 may preferably be a high flow piston pump or a vacuum pump (flow rate depending on the application, e.g., 0 ml / min to 50 ml / min). When the system 100 is configured as shown in FIG. 1, the fourth fluid pump 142 can be operated to direct the external sample from the sample source 134 directly through the sample loop 110 towards the drain 140 (e.g., at a flow rate of about 30 ml / min) until an analysis sample representative of the external sample is loaded into the sample loop 110. Alternatively, a vacuum source may be used instead of the fourth fluid pump 142 to aspirate the external sample through the sample loop 110. In either case, the loaded analysis sample can then be analyzed by switching the first multiport valve 104 to the second valve position as described herein and shown in FIG. 2.

[0075] As shown in FIGS. 1 and 2, when both the valve 106 and the valve 108 are maintained in the first valve position, one or more samples provided at the sample source 134 can be analyzed without inline dilution as described herein. The continuous flow path from the sample source 134 to the analysis sample loop 110 allows the (multiple) external samples to be advantageously flowed directly into the analysis sample loop without passing through the dilution module, minimizing the time required for each analysis.

[0076] Alternatively, system 100 can also be configured to enable in-line dilution of one or more samples provided at sample source 134 to a required dilution level of the instrument, as determined based on an initial analysis of an undiluted external sample, for example, as described herein.

[0077] And the third multiport valve 108 is connected to an external sample reservoir 144. This external sample reservoir is configured as a sample loop connected to ports 1 and 4 of valve 108. This sample loop may have a coil of thin tubing (e.g., with an inner diameter of 1 mm or 2 mm) having a volume sufficient to hold an external sample for subsequent dilution and analysis by the analyzer 124. As shown in FIG. 3, when the third multiport valve 108 and the second multiport valve 106 are each switched to the second valve position, the fourth fluid pump 142 allows an external sample to flow from the sample source 134 through the sample source line 136, the external sample reservoir 144, the sample transfer line 132, the valve 106, and the drain line 148 to the drain 140 (e.g., at a flow rate of about 30 ml / min), so that the external sample can be loaded into the external sample reservoir 144. This flow continues at least until the external sample reservoir 144 holds a representative sample of the external sample. The valve assembly 102 can be configured to allow the fourth fluid pump 142 to flow an external sample from the sample source 134 to the external sample reservoir 144.

[0078] System 100 has a first fluid pump 150. The first fluid pump 150 flows a second carrier fluid 152 through a carrier fluid line 154 to port 3 to enter the third multiport valve 108. System 100 also has a second fluid pump 156. By this second fluid pump 156, as shown in FIGS. 3 and 4, regardless of whether the third multiport valve 108 is in the first valve position or the second valve position, the diluent 158 flows through a diluent fluid line 160 into the valve 108 and exits from port 2 to enter port 7. The first fluid pump 150 and the second fluid pump 156 are suitable for syringe pumps or may be other positive displacement pumps such as piston pumps, and can accurately control the relative flow rates of the second carrier fluid 152 and the diluent 158 so as to achieve the target dilution rate of the external sample held in the external sample reservoir 144.

[0079] In one embodiment, the first fluid pump 150 is controllable within a flow rate range of 0.04 ml / min to 5.0 ml / min, the second fluid pump 156 is controllable within a flow rate range of 5.0 ml / min to 9.96 ml / min, and a dilution factor within the range of 2 to 250 is obtained at a constant total flow rate of 10 ml / min. In such an embodiment, since the minimum dilution factor is 2, it is found that the volume of the external sample reservoir 144 may be approximately equal to (or even somewhat smaller than) the volume of the analytical sample loop 110. In contrast, for prior art designs that cannot bypass the dilution module, the first sample loop needs to be sized to transfer the undiluted sample to the analytical sample loop, so a relatively large first sample loop may be required. The present invention thus advantageously enables a smaller amount of external sample to be rapidly loaded into the external sample reservoir 144 than is possible with prior art designs, and the degree of this advantage corresponds to the minimum dilution factor.

[0080] As shown, system 100 may include only a single first fluid pump 150 and a single second fluid pump 156, but it will be understood that system 100 may alternatively include two or more first fluid pumps 150 and / or two or more second fluid pumps 156 configured in parallel and having different flow rate ranges. This advantageously can expand the range of relative flow rates (v / v) of the second carrier fluid 152 and the diluent 158 that can be supplied, thus enabling a broader range of sample dilution to be achieved. The first fluid pump 150 and the second fluid pump 156 can obtain the second carrier fluid 152 and the diluent 158 from a single diluent source 162, as shown in FIGS. 3 and 4, and in fact, the first carrier fluid 116 can also be obtained from the same source. However, it will be understood that the second carrier fluid 152, the diluent 158, and the first carrier fluid 116 may in principle be obtained from different sources and may have different compositions.

[0081] When the external sample reservoir 144 comes to hold a representative external sample loaded from the sample source 134, as shown in FIG. 4, the third multiport valve 108 is switched to return to the first valve position. The first fluid pump 150 operates to flow the second carrier fluid 152 at a predetermined flow rate through the external sample reservoir 144, push the external sample out of the valve 108, and exit through port 2 into the inside of the diluted sample transfer line 146. The second fluid pump 156 operates to flow the diluent 158 through the valve 108 and exit into the inside of the diluted sample transfer line 146 through port 2. Port 2 of the valve 108 functions as a sample dilution confluence section 164, where the external sample contacts and mixes with the diluent 158 to produce a diluted sample, the dilution level of which is controlled by the relative flow rates of the second carrier fluid 152 and the diluent 158.

[0082] System 100 may be configured to introduce bubbles, such as air 166, to separate the second carrier fluid 152 from the external sample when the second carrier fluid 152 flows through the external sample reservoir 144. For example, as shown in FIG. 3, while valves 108 and 106 are in the second valve position, after flowing the second carrier fluid 152 and the diluent 158 through valves 108 and 106, the second multiport valve 106 is switched to the first valve position, and the flow directions of the first fluid pump 150 and the second fluid pump 156 are reversed. Air 166 is drawn into the diluted sample transfer line 146 through the gas inlet 168, where the liquid backflow continues until the air is just recovered into the carrier fluid line 154 and the diluent fluid line 160, that is, until the bubbles just pass through ports 3 and 7 of valve 108 respectively. The resulting bubbles thus physically separate the second carrier fluid 152 from the sample when the carrier fluid flows through the external sample reservoir 144 and pushes the external sample towards the sample confluence section 164 (one is ahead of the diluted sample and the other is behind the external sample). This prevents or reduces the unwanted dilution of the external sample before the intended dilution occurs at the sample dilution confluence section 164.

[0083] As shown in FIGS. 3 and 4, system 100 is configured such that an external sample is loaded into the external sample reservoir 144 through port 4 and supplied from port 1 to the sample dilution confluence section 164 ("first in, first out"). Alternatively, the sample source line 136 can be connected to port 6 of valve 108 and the sample transfer line 132 can be connected to port 5 so that the external sample is loaded into the analysis sample loop 110 through port 1 and supplied from port 1 to the sample dilution confluence section 164 ("last in, first out").

[0084] Continuing to refer to FIG. 4, the diluted sample generated in the sample dilution junction 164 flows through the analysis sample loop 110 via the valve 106 (in the second valve position) and the load line 112 to the drain 140, and this flow continues until at least the analysis sample loop 110 holds a representative sample of the diluted sample. The fourth fluid pump 142 is preferably bypassed by switching the bypass valve 138 to the second configuration. This is because there is no need to generate flow and it may interfere with the accurate operation of pumps 150 and 156.

[0085] The analysis sample loaded into the analysis sample loop 110 is then supplied to the nebulizer 122 via the sample supply line 120 by switching the first multi-port valve 104 to the second valve position, as shown in FIG. 5. As also shown in FIG. 5, when the valve 108 is in the second valve position, the external sample reservoir 144 may then be washed with a rinse solution provided via the sample source line 136, e.g., from an autosampler, during the analysis step. The external sample reservoir 144 is then reloaded with an external sample from the sample source 134, thus facilitating a rapid turnaround between successive in-line dilution analyses. Optionally, during the analysis of the diluted sample, the flow of the second carrier fluid 152 and / or the diluent 158 may continue to flush the diluted sample from the flow path from the sample dilution junction 164 to the drain 140. If necessary, pumps 150 and 156 may be refilled with the second carrier fluid 152 and the diluent 158 from the diluent source 162 during the analysis step.

[0086] System 100 thus enables an external sample provided from sample source 134 to be accurately diluted inline if necessary. Inline dilution is performed in a three-step process, namely, a first step of loading the external sample into external sample reservoir 144, a second step of unloading the external sample reservoir, diluting the sample, and reloading it into analysis sample loop 110, and a third step of unloading the diluted sample into analyzer 124. This inevitably increases the time required for each analysis. However, as described herein, system 100 advantageously enables samples that do not require dilution or samples that require an initial analysis without dilution to bypass the dilution module including external sample reservoir 144 and be analyzed in only two steps, improving the productivity of the instrument.

[0087] Figures 6 to 9 show a sample supply system 200 according to an embodiment of the present invention. System 200 has a valve assembly 202 including a first multiport valve 204 and a second multiport valve 206. Valve 204 is switchable between a first valve position and a second valve position, and three internal flow channels in the valve provide different connection methods between two ports of the valve. Valve 206 has two internal flow channels (shown by dashed lines in Figures 6 to 9) and four ports, is switchable between a first valve position, a second valve position, and a third valve position, and different connection methods between the ports are provided by a plurality of flow channels.

[0088] The first multiport valve 204 is connected to an analysis sample loop 210 having a coil of small-diameter tubes having a volume sufficient to hold an analysis sample for subsequent analysis in the analyzer 224. The valve 204 is also connected to a second multiport valve 206 via a load line 212. As shown in FIG. 6, when the first multiport valve 204 is in the first valve position, an undiluted or diluted sample to be analyzed can be loaded into the analysis sample loop 210 by flowing the sample from the load line 212, through the analysis sample loop 210, out of the valve 204 and into the drain line 213, and this flow continues until at least the analysis sample loop 210 holds a representative sample.

[0089] The system 200 further includes a third fluid pump 214 (e.g., a peristaltic pump) that flows a first carrier fluid 216 (also known as a rinse fluid) to the first multiport valve 204 via a carrier fluid line 218. As shown in FIG. 6, when the first multiport valve 204 is in the first valve position, the pump 214 flows the first carrier fluid 216 directly to the nebulizer 222 through the valve 204 and via the sample supply line 220.

[0090] Once an analysis sample representative of the undiluted or diluted sample to be analyzed is loaded into the analysis sample loop 210, the analysis sample is then supplied to the nebulizer 222 via the sample supply line 220 by switching the first multiport valve 204 to the second valve position, as shown in FIG. 7. The flow of the first carrier fluid 216 thus bypasses through the analysis sample loop 210 and pushes the analysis sample from the valve 204 through the sample supply line 220 to the nebulizer 222, where the analysis sample is sprayed and subsequently analyzed in the analyzer 224 (e.g., an ICP-OES analyzer or an ICP-MS analyzer).

[0091] Similar to system 100, system 200 may optionally include a bubble injector (not shown) that injects gas separation bubbles into the carrier fluid line 218 immediately before connection to 204, and a fluid pump (not shown) for flowing an internal standard solution through the sample supply line 220. The analytical sample loop 210 may preferably be configured for either a last-in-first-out or first-in-first-out operation.

[0092] The second multiport valve 206 is connected to the sample source 234 via the sample source line 236. The sample source 234 is configured to provide one or more external samples for analysis and may be an autosampler or other sample supply device as disclosed herein. As shown in FIG. 6, the first multiport valve 204 and the second multiport valve 206 are each in the first valve position. The valve assembly 202 is thus configured to allow the flow of external samples along a continuous flow path from the sample source 234 to the analytical sample loop 210 (via the sample source line 236, valve 206, load line 212, and valve 204).

[0093] System 200 includes a fourth fluid pump 242 disposed in the flow path between the valve 204 and the drain 240 downstream of the first multiport valve 204, preferably a high flow piston pump or a vacuum pump. The fourth fluid pump 242 can thus be operated to flow the external sample directly from the sample source 234 through the sample loop 210 and towards the drain 240 until an analytical sample representative of the external sample is loaded into the sample loop 210. The analytical sample thus loaded can then be analyzed by switching the first multiport valve 204 to the second valve position, as described herein and shown in FIG. 7.

[0094] As shown in FIGS. 6 and 7, when the valve 206 is maintained in the first valve position, one or more samples provided from the sample source 234 can be analyzed without inline dilution as described herein. Due to the continuous flow path from the sample source 234 to the analytical sample loop 210, (multiple) external samples are advantageously flowed directly into the analytical sample loop without passing through the dilution module, minimizing the time required for each analysis.

[0095] However, the system 200 can also be configured to enable inline dilution of one or more samples provided from the sample source 234 to a dilution level required by the instrument, which is determined, for example, based on an initial analysis of an undiluted external sample as described herein.

[0096] The second multi-port valve 206 is connected in the system 200 to an external sample reservoir 244 configured as a line connected to the second multi-port valve 206 at one end and to the switching valve 251 and the first fluid pump 250 at the other end, rather than as a sample loop connected to two ports of the multi-port valve. When the switching valve 251 is configured to connect the pump 250 to the external sample reservoir 244 (as seen in the figure), the pump 250 can flow fluid in both directions: in a direction to fill the external sample reservoir 244 from the valve 206 and in a reverse direction to precisely control the flow of the external sample from the external sample reservoir 244 for dilution. The pump 250 may thus be a syringe pump or other positive displacement pump, such as a piston pump, capable of accurately controlling the fluid flow rate within the required range. The external sample reservoir 244 may have a coil of small-diameter tubing (e.g., 1 mm or 2 mm inner diameter) having a volume sufficient to hold the external sample for subsequent dilution and analysis in the analyzer 224.

[0097] Preferably, the external sample to be diluted and analyzed does not contact the pump 250 during loading and unloading of the external sample reservoir 244, thus avoiding sample contamination. Therefore, in some embodiments, the pump 250 may be operated with a carrier fluid in its internal space, which has the additional advantage of minimizing pump contamination. For example, as shown in FIG. 8, when the second multi-port valve 206 is switched to the third valve position, the pump 250 draws the carrier fluid provided at the sample source 234 into its internal space through the external sample reservoir 244 (optionally, by reconfiguring the switching valve 251, discharging any excess carrier fluid to the drain 241 as necessary). Alternatively, the diluent 258 may be used to fill the external sample reservoir 244 and the pump 250 (when the valve 206 is in the first position, as seen in FIG. 7).

[0098] When the second multi-port valve 206 is in the third valve position, the external sample can be loaded from the sample source 234 to the external sample reservoir 244 via the sample source line 236 using the pump 250. Preferably, the carrier fluid previously loaded into the external sample reservoir 244 is drawn into the internal space of the first fluid pump 250, and this flow stops before the external sample enters the switching valve 251. Optionally, a gas separation bubble may be introduced to separate the external sample from the carrier fluid, avoiding or limiting the mixing of the two fluids so that the external sample reservoir 244 holds a representative aliquot of the external sample. The valve assembly 202 can be configured to allow the first fluid pump 250 to flow the external sample from the sample source 234 to the external sample reservoir 244.

[0099] Optionally, the external sample can be loaded into the external sample reservoir 244 while performing the analysis of the analysis sample previously loaded in the analysis sample loop 210. The multiport valve 204 may be maintained in the second valve position, as seen in FIG. 8, and a continuous flow of the first carrier fluid 216 to the nebulizer may be used to wash the analysis sample loop 210 and the nebulizer while a new external sample is being loaded into the external sample reservoir 244. The valve 204 may then be switched to the first valve position when ready to load another analysis sample.

[0100] When the external sample reservoir 244 holds a representative external sample loaded from the sample source 234, as shown in FIG. 9, the second multiport valve 206 is switched to the second valve position and the first multiport valve 204 is switched to the first valve position (if not already done). The first fluid pump 250 is activated to flow the external sample from the external sample reservoir 244 back to the valve 206, typically using the carrier fluid inside the pump to push out the external sample. The pump 250 is designed such that the reverse flow towards the valve 206 required to transfer the external sample from the external sample reservoir 244 for dilution does not exceed its internal volume. The second fluid pump 256 (preferably a syringe pump selectively connectable to the valve 206 or the source of the diluent 258 via a switching valve 257) is activated to flow the diluent 258 to the valve 206, where the diluent contacts the flow of the external sample at the sample dilution confluence 264 inside the valve 206 to dilute the external sample and produce a diluted sample. The first fluid pump 250 and the second fluid pump 256 are configured to accurately control the relative flow rates of the external sample from the external sample reservoir 244 and the diluent 258 to achieve the target dilution rate.

[0101] The system 200 can optionally be configured to introduce (a plurality of) discrete bubbles, e.g., bubbles from the diluent line 260 to travel ahead of the diluted sample and / or bubbles to travel after the undiluted external sample, to separate the external sample from the liquid in the pump 250.

[0102] Continuing to refer to FIG. 9, the diluted sample generated in the sample dilution junction 264 flows through the analysis sample loop 210 via the load line 212 to the drain 240 (preferably, as shown in FIGS. 1-5, bypassing the fourth fluid pump 242 via, for example, a one-way valve 238 or alternatively a switching valve), and this flow continues until at least the analysis sample loop 210 holds a representative sample of the diluted sample. At the same time, the first carrier fluid (also known as the rinse fluid) is flowed directly through the valve 204 to the nebulizer 222. The analysis sample thus loaded into the analysis sample loop 210 is then supplied to the nebulizer 222 via the sample supply line 220 by switching the first multi-port valve 204 to the second valve position, as described herein.

[0103] Optionally, during the analysis of the diluted sample, the flow of the diluent 258 may continue for a time sufficient to flush the remaining diluted sample from the flow path from the sample dilution junction 264 to the drain 240. (Again, as seen in FIG. 8) When the valve 206 is then switched to the third valve position, the external sample reservoir 244 can be washed with a rinse fluid provided via the sample source line 236, for example, from an autosampler. The external sample reservoir 244 is then reloaded with an external sample from the sample source 234, thus enabling a rapid turn-around between successive in-line dilution analyses. Alternatively, (again, as seen in FIG. 7) when the valve 206 is switched to the first valve position, the load line 212 may then be washed with a rinse fluid provided via the sample source line 236, for example, from an autosampler, in preparation for a subsequent analysis, with or without dilution. The external sample reservoir 244 may be washed with the diluent 258 when analyzing the sample without dilution, as described herein with reference to FIGS. 6 and 7, for example.

[0104] System 200 enables an external sample provided from a sample source 234, if necessary, to be accurately diluted inline in a dilution module including an external sample reservoir 244. This necessarily lengthens the time taken for each analysis. However, as described herein, system 200 is advantageously configured such that samples that do not require dilution, or samples that require an initial analysis without dilution, can bypass the external sample reservoir 144, thus improving the productivity of the instrument.

[0105] FIG. 10 shows a sample supply system 300 according to an embodiment of the present invention. System 300 is a variant of system 200 without a fluid pump 256 for pumping a diluent 258. When inline dilution of the sample is required, the external sample is loaded into the external sample reservoir 244 as described herein for system 200. As shown in FIG. 10, the second multiport valve 206 is then switched to the second valve position, and the first multiport valve is switched to the first valve position (if not already done). The first fluid pump 250 is activated to flow an external sample back from the external sample reservoir 244 to the valve 206. The fluid pump 242 (operating here in place of the second fluid pump 256) is activated to flow the diluted sample from the sample dilution junction 264 through the analysis sample loop 210 and to the drain 240 via the load line 212. The fluid pump 242 accurately controls the flow rate of the overall diluted sample, while the first fluid pump 250 accurately controls the flow rate of the external sample. The diluent 258 is drawn into the sample dilution junction 264 at the required flow rate, i.e., the difference between the flow rate of pump 242 and the flow rate of pump 250. In this way, the fluid pump 242 indirectly controls the flow rate of the diluent 258 to the sample dilution junction, and thus controls the dilution level of the diluted sample loaded into the analysis sample loop 210.

[0106] In system 300, fluid pump 242 serves mainly two roles, namely (1) loading an external sample into the analysis sample loop 210, which preferably operates at high speed but not necessarily accurately (when analyzing an undiluted sample), and (2) controlling the flow of the diluent, which typically operates at low speed but must be accurate (when analyzing a diluted sample). The pump 242 may, if necessary, be implemented as two parallel pumps in order to best achieve both purposes.

[0107] In another contemplated variation of system 200 (not shown), the analysis sample loop 210 is replaced by an analysis sample reservoir in the form of a line connected to valve 204 at one end and to the first fluid pump 242 at the other end. The diluted or undiluted sample to be analyzed is thus pumped by pump 242 into the analysis sample reservoir. When a representative analysis sample of the result is analyzed, pump 242 reverses direction (while switching valve 204 simultaneously) to allow the analysis sample to flow to the analyzer 224. The pump 242 in this embodiment is designed such that backflow into the analyzer does not exceed its internal volume, eliminating the need for a carrier fluid to move the analysis sample from the analysis sample reservoir for analysis. In this embodiment, the analysis sample reservoir has a design and operation similar to the external sample reservoir 244.

[0108] <Spectrometer> The present invention also relates to a spectrometer having a sample supply system as disclosed herein and an analysis device. The analysis device may be permanently connected or removably connected to the sample supply line of the analysis sample device. In some embodiments, the analysis device is a conventional analysis device for a plasma spectrometer and thus includes components such as a nebulizer, a spray chamber for classifying the aerosolized sample, a plasma torch (powered from an RF generator if necessary), and an optical detector or an ion mass detector. The spectrometer may be an ICP - OES spectrometer and / or an ICP - MS spectrometer. Alternatively, it may be a microwave plasma spectrometer.

[0109] A computing device may be provided to control the operation of the spectrometer. The computing device may include one or more tangible, non-transitory computer-readable media having computer-executable instructions for performing a computer-implemented method for controlling the operation of the spectrometer according to the principles disclosed herein. Typically, the computer-implemented method is automatically executed on a computer processor that either comprises the spectrometer or is provided separately from the spectrometer. The computer processor may include a software application installed to perform one or more steps of the computer-implemented method. In alternative embodiments, the software application may be a cloud-based application accessible via a network such as the Internet. In some embodiments, the software application may be remotely accessible via a local network.

[0110] In some embodiments, the spectrometer controlled by the computing device is thus adapted to supply an external sample for spectroscopic analysis by either method (a) or method (b). Method (a) is a computer-implemented method for spectroscopic analysis of an external sample without inline dilution, and method (b) is a computer-implemented method for spectroscopic analysis of an external sample with inline dilution.

[0111] Method (a) comprises (i) flowing an external sample without dilution along a continuous flow path from a sample source to an analysis sample reservoir, and (ii) subsequently supplying the external sample from the analysis sample reservoir to an analyzer for spectroscopic analysis and.

[0112] Method (b) comprises (i) flowing an external sample from a sample source to an external sample reservoir, and (ii) subsequently flowing the external sample from the external sample reservoir to a sample dilution junction (iii) simultaneously flowing a diluent into the sample dilution and confluence section to dilute the external sample and generate a diluted sample; (iv) flowing the diluted sample from the sample dilution and confluence section into the analytical sample reservoir; (v) subsequently, for spectroscopic analysis, supplying the diluted sample from the analytical sample reservoir to the analytical apparatus and the like.

[0113] In some embodiments, a spectrometer controlled by a computing device supplies an external sample for spectroscopic analysis by method (a), determines a target dilution ratio of the external sample based on the spectroscopic analysis of the external sample in method (a), and supplies a diluted sample containing a first external sample and a diluent for spectroscopic analysis by method (b). The first fluid pump and the second fluid pump of the sample supply device are controlled by the computing device such that the first external sample and the diluent flow at a relative flow rate suitable for achieving the target dilution ratio in the diluted sample. Determining the target dilution ratio may include determining that the concentration of the analyte in the external sample measured in method (a) exceeds a predetermined maximum concentration (for example, the upper limit of the calibration curve range), and calculating or estimating the target dilution ratio of the external sample such that the analyte concentration of the diluted sample is below the predetermined maximum concentration.

[0114] <Method of analysis> The present invention also relates to a method of analysis using the spectrometer disclosed herein. As schematically shown in FIG. 11, the method of analysis 1100 includes a step 1110 of providing one or more external samples at a sample source for analysis, and a step 1130 of analyzing at least a first sample of the one or more external samples by a first analysis method without dilution of the first sample. In some embodiments, the method of analysis 1100 further includes a step 1150 of analyzing at least a first sample or a second sample of the one or more external samples by a second analysis method with in-line dilution of the first sample or the second sample.

[0115] The first analysis method in step 1130 is (i) Sub-step 1132 of flowing a first sample along a continuous flow path from a sample source to an analysis sample reservoir; (ii) Subsequently, sub-step 1134 of supplying the first sample from the analysis sample reservoir to an analyzer for spectroscopic analysis; and it includes.

[0116] The second analysis method of step 1150 is (i) Sub-step 1152 of flowing a first sample or a second sample from a sample source to an external sample reservoir; (ii) Following sub-step 1152, sub-step 1154 of flowing the first sample or the second sample from the external sample reservoir to a sample dilution confluence section; (iii) Simultaneously with sub-step 1154, flowing a diluent to the sample dilution confluence section to dilute the first sample or the second sample to generate a diluted sample in sub-step 1f; (iv) Sub-step 1158 of flowing the diluted sample from the sample dilution confluence section to an analysis sample reservoir; (v) Following sub-step 1158, sub-step 1160 of supplying the diluted sample from the analysis sample reservoir to an analyzer for spectroscopic analysis; and it includes.

[0117] In some embodiments, method 1100 includes determining a target dilution rate of the first sample based on spectroscopic analysis of the first sample in sub-step 1134, and analyzing the first sample (i.e., the same external sample) in step 1150 by the second analysis method. The first fluid pump and the second fluid pump of the sample supply system are controlled to flow the first sample and the diluent at a relative flow rate suitable for achieving the target dilution rate in the diluted sample in sub-step 1154 and sub-step 1156.

[0118] Determining the target dilution rate may include determining that the analyte concentration in the first sample is greater than a predetermined maximum concentration (e.g., the upper limit of the calibration curve range), and calculating or estimating the target dilution rate of the first sample such that the analyte concentration of the diluted sample generated in sub-step 1156 is less than the predetermined maximum concentration. The method according to such an embodiment can thus be useful for in-line dilution of samples where one or more analytes are found to be out of range in the initial analysis.

[0119] In some embodiments, method 1100 includes providing a plurality of external samples to a sample source for analysis in step 1110, analyzing the plurality of external samples by a first analysis technique in step 1130, and based on the spectroscopic analysis of the plurality of external samples obtained in sub-step 1134, identifying out-of-range samples among the plurality of external samples that have an analyte concentration greater than a predetermined maximum concentration (e.g., the upper limit of the calibration curve range), and analyzing the out-of-range samples (if identified) by a second analysis technique in step 1150. The first fluid pump and the second fluid pump are controlled to flow the out-of-range sample and the diluent at a relative flow rate suitable for providing an analyte concentration of the diluted sample that is lower than the predetermined maximum concentration in sub-steps 1154 and 1156 of the second analysis technique.

[0120] The method according to such an embodiment is useful for spectroscopic analysis of a series of external samples and then re-analyzing only the samples found to be out of range using appropriate in-line dilution to bring the analyte concentration within the analysis range. This technique provides excellent instrument productivity because the samples bypass the dilution system of the sample supply system in the initial analysis.

[0121] In some embodiments, the methods disclosed herein can be used to generate calibration data for a calibration curve. Method 1100 includes, at step 1100, providing a calibration sample having one or more analytical species of known concentration for analysis to a sample source; at step 1130, analyzing the calibration sample by a first analytical technique and supplying the calibration sample to an analyzer for spectroscopic analysis; and at step 1150, analyzing the calibration sample one or more times by a second analytical technique and supplying one or more diluted calibration samples having one or more analytical species of known concentration for spectroscopic analysis to the analyzer.

[0122] Next, a method of analysis according to an embodiment of method 1100 will be described with reference again to FIGS. 1-5 showing an ICP-OES spectrometer or an ICP-MS spectrometer having a sample supply system 100 and an analyzer 124.

[0123] The method includes providing one or more external samples at a sample source 134 for analysis (step 1110). Preferably, sampler 134 is an autosampler and a plurality of external samples are provided to the autosampler, for example in vials, for analysis. The method includes analyzing at least a first sample of the samples provided at sample source 134 by a first analytical technique without dilution of the first sample (step 1130). Optionally, the method may further include analyzing a first sample or a second sample of the one or more external samples by a second analytical technique with in-line dilution of the first sample or the second sample (step 1150).

[0124] In step 1130, the first analysis method requires that, as shown in FIGS. 1 and 2, the second multiport valve 106 and the third multiport valve 108 be held in the first valve position. The first multiport valve 104 is also initially in the first valve position as shown in FIG. 1, and the valve assembly 102 is configured to provide a continuous flow path from the sample source 134 to the analysis sample loop 110. The fourth fluid pump 142 disposed downstream of the analysis sample loop 110 is activated to flow the first sample towards the drain 140 along the continuous flow path from the sample source 134 to the analysis sample loop 110 (sub-step 1132). The flow rate may be as large as, for example, about 30 ml / min to enable a rapid load of the first sample, and the flow continues for a sufficient time to wash the line and ensure that a representative aliquot of the first sample is obtained in the analysis sample loop 110. At the same time, the third fluid pump 114 and the fifth fluid pump 128 flow a constant flow rate of the first carrier fluid 116 (e.g., 0.3 ml / min for ICP-MS, 1 ml / min for ICP-OES) and the internal standard solution 130 through the first multiport valve 104 to the nebulizer 122.

[0125] When a representative analytical sample of the first sample is loaded into the analysis sample loop 110, as shown in FIG. 2, by switching the first multiport valve 104 to the second valve position, the analytical sample is then supplied to the nebulizer 122 via the sample supply line 120. The flow of the first carrier fluid 116 thus bypasses through the analysis sample loop 110, pushing the analytical sample out of the valve 104 (where it mixes with the flow of the internal standard solution), and pushing it out via the sample supply line 120 to the nebulizer 122, where the analytical sample is sprayed and subsequently analyzed in the analyzer 124 for spectroscopic analysis (sub-step 1134). If necessary, when the first multiport valve 104 is switched to the second valve position to physically separate the first carrier fluid 116 from the first sample, bubbles are injected by the bubble injector 126.

[0126] After the first sample is supplied for analysis, the first multi-port valve 104 is switched to return to the first valve position, allowing the flow of the first carrier fluid 116 to be sent directly through the valve 104 again to the nebulizer. Optionally, the continuous flow path from the sample source 134 to the analysis sample loop 110 and towards the drain 140 is washed with a rinse fluid between analyses. For example, the rinse fluid may be provided from a rinse fluid source in the autosampler.

[0127] As shown in FIGS. 1 and 2, when both the valve 106 and the valve 108 are maintained in the first valve position, any number of samples provided at the sample source 134 can be sequentially analyzed by the first analysis method as described herein. Due to the continuous flow path from the sample source 134 to the analysis sample loop 110, the (multiple) external samples are advantageously flowed directly into the analysis sample loop 110 without passing through the external sample loop 144, thus minimizing the total time required for each analysis.

[0128] In step 1150, a sample (either the first sample or the second sample) among the one or more external samples may be analyzed by the second analysis method. Initiating the second analysis method requires that, as shown in FIG. 3, with the first multi-port valve 104 in the first valve position, the second multi-port valve 106 and the third multi-port valve 108 are switched to the second valve position. The valve assembly 102 is thus configured to allow the flow of external samples from the sample source 134 to the external sample reservoir 144. The fourth fluid pump 142 is activated to flow the first sample or the second sample from the sample source 134 to the external sample reservoir 144 and towards the drain 140 (sub-step 1152). The flow rate may be as high as, for example, about 30 ml / min to allow for a rapid loading of the sample, and the flow continues for a sufficient time to wash the line and ensure that a representative aliquot of the first sample or the second sample is obtained in the external sample reservoir 144.

[0129] The second method may also include a sub-step of preparing a supply system for the second carrier fluid 152 and the diluent 158. The bypass valve 138 may be switched to the second configuration (as also seen in FIG. 3), and the first fluid pump 150 and the second fluid pump 156 may be operated to wash the analysis sample loop 110 and other lines in the flow path to the drain 140 with the second carrier fluid 152 and the diluent 158. Optionally, as previously described herein, the second multi-port valve 106 may be temporarily switched to the first valve position and the flow directions of the first fluid pump 150 and the second fluid pump 156 may be reversed to introduce separated air bubbles into the carrier fluid line 154 and the diluent fluid line 160.

[0130] When the external sample reservoir 144 holds a representative sample of the first or second sample and the supply system for the second carrier fluid 152 and the diluent 158 is properly prepared, the third multi-port valve 108 is switched back to the first valve position as shown in FIG. 4. The first fluid pump 150 is operated to flow the second carrier fluid 152 through the external sample reservoir 144 and push the first or second sample out of the valve 108 through the sample dilution junction 164 (sub-step 1154). The second fluid pump 156 is operated to flow the diluent 158 through the valve 108 and out of the valve 108 through the sample dilution junction 164, thereby contacting and mixing the first or second sample with the diluent 158 to produce a diluted sample (sub-step 1156). The dilution level of the diluted sample is controlled by the relative flow rates of the second carrier fluid 152 and the diluent 158.

[0131] Continuing to refer to Figure 4, the diluted sample flows from the sample dilution junction 164 through the valve 106 (in the second valve position) to the analytical sample loop 110 and towards the drain 140, and this flow continues until at least the analytical sample loop 110 holds a representative aliquot of the diluted sample (sub-step 1158). The diluted analytical sample loaded into the analytical sample loop 110 is then supplied to the nebulizer 122 by switching the first multi-port valve 104 to the second valve position in a manner similar to that described herein for the first analytical technique, as shown in Figure 5 (sub-step 1160).

[0132] The valve 108 may be switched to the second valve position simultaneously with the valve 104, as shown in Figure 5, whereby the flow path from the sample source 134 through the external sample reservoir 144 to the drain 140 may be rinsed with the rinse liquid during the intervals between analyses. For example, the rinse liquid may be provided from a rinse liquid source in the autosampler. The flow of the second carrier fluid 152 and / or the diluent 158 may also be continued to flush the diluted sample out of the flow path from the sample dilution junction 164 to the drain 140. If necessary, the pumps 150 and 156 may then be refilled with the second carrier fluid 152 and the diluent 158 from the diluent source 162 again.

[0133] Another sample of the plurality of external samples provided at the sample source 134 is then reloaded into the external sample reservoir 144 to facilitate a rapid turnaround between successive in-line dilution analyses.

[0134] As will be apparent to those skilled in the art, a similar method of analysis (according to another embodiment of method 1100) may be performed using an ICP-OES spectrometer or an ICP-MS spectrometer including the sample supply system 200 or the sample supply system 300 and the analyzer 224, as shown in Figures 6-10.

[0135] The methods of analysis described earlier in this specification generally involve the analysis of one or more samples in which at least one sample is spectrally analyzed without inline dilution. As described earlier, such methods advantageously enable the rapid analysis of undiluted samples because the external sample reservoir is bypassed when transferring the sample from the sample source to the analytical sample reservoir. On the other hand, the sample supply system disclosed herein is also suitable for analyzing a sample or a series of samples that are diluted inline to a defined dilution level, i.e., a dilution level that is not determined based on an initial undiluted analysis.

[0136] The present disclosure thus also provides a method of analysis using a spectrometer as disclosed herein, the method comprising providing one or more external samples at a sample source for analysis, and analyzing at least a first sample of the one or more external samples by an analytical technique with inline dilution of the first sample, the analytical technique comprising: (i) flowing the first sample from the sample source to an external sample reservoir; (ii) subsequently flowing the first sample from the external sample reservoir to a sample dilution junction; (iii) simultaneously flowing a diluent to the sample dilution junction to thereby dilute the first sample and produce a diluted sample; (iv) flowing the diluted sample from the sample dilution junction to an analytical sample reservoir; and (v) subsequently supplying the diluted sample from the analytical sample reservoir to an analytical device for spectral analysis.

[0137] Those skilled in the art will understand that the invention described herein is capable of variations and modifications other than those specifically described. It will be understood that the invention includes all such variations and modifications that fall within the spirit and scope of the invention.

Claims

1. A valve assembly having one or more valves for receiving an external sample from a sample source, An external sample reservoir connected to a sample dilution junction through the valve assembly, wherein the valve assembly can selectively permit (i) the flow of the external sample from the sample source to the external sample reservoir, and (ii) the flow of the external sample from the external sample reservoir to the sample dilution junction. An external sample reservoir, A first fluid pump for controlling the flow of the external sample from the external sample reservoir to the sample dilution junction, A second fluid pump for controlling the flow of a diluent to the sample dilution junction and diluting the external sample to generate a diluted sample, An analysis sample reservoir for supplying the contained analysis sample to an analyzer of an analytical instrument, wherein the analysis sample reservoir is connected to the sample dilution junction through the valve assembly, and the valve assembly can selectively permit (i) the flow of the external sample bypassing the external sample reservoir along a continuous flow path from the sample source to the analysis sample reservoir, and (ii) the flow of the diluted sample from the sample dilution junction to the analysis sample reservoir. An analysis sample reservoir, A sample supply system for an analytical instrument comprising the above components.

2. The analysis sample reservoir is configured as an analysis sample loop connected to two ports of a first multiport valve of the valve assembly, The analysis sample can be loaded into the analysis sample loop when the first multiport valve is in a first valve position, The analysis sample can be supplied from the analysis sample loop to the analyzer when the first multiport valve is switched to a second valve position. The sample supply system according to Claim 1.

3. The sample supply system further comprises a third fluid pump for flowing a first carrier fluid through the first multiport valve, The first multiport valve can be configured to directly flow the first carrier fluid through the first multiport valve to the analyzer when the first multiport valve is in the first valve position, and to bypass the first carrier fluid through the analysis sample loop when the first multiport valve is switched to the second valve position, and to supply the analysis sample from the analysis sample loop to the analyzer. The sample supply system according to Claim 2.

4. The sample supply system according to claim 3, further comprising a bubble injector that injects a gas bubble for separating the first carrier fluid from the analysis sample when the first carrier fluid flows through the analysis sample loop.

5. The sample supply system according to any one of claims 1 to 4, further comprising a fourth fluid pump or a vacuum source for flowing the external sample along the continuous flow path from the sample source to the analysis sample reservoir.

6. The sample supply system according to claim 5, wherein the fourth fluid pump or the vacuum source is bypassed when the diluted sample flows from the sample dilution junction to the analysis sample reservoir.

7. The sample supply system according to claim 5 or 6, wherein the valve assembly is configurable to allow the fourth fluid pump or the vacuum source to flow the external sample from the sample source to the external sample reservoir.

8. The sample supply system according to any one of claims 1 to 6, wherein the valve assembly is configurable to allow the first fluid pump to flow the external sample from the sample source to the external sample reservoir.

9. The valve assembly includes a second multi-port valve connected to the analysis sample reservoir, The second multi-port valve is switchable to at least a first valve position that allows the flow of the external sample along the continuous flow path from the sample source to the analysis sample reservoir and a second valve position that allows the flow of the diluted sample from the sample dilution junction to the analysis sample reservoir. The sample supply system according to any one of claims 1 to 8.

10. The sample supply system according to claim 9, wherein the second multi-port valve is switchable to a third valve position that allows the flow of the external sample from the sample source to the external sample reservoir.

11. The sample supply system according to claim 10, wherein when the second multi-port valve is switched to the second valve position, the second fluid pump controls the flow of the diluent through the second multi-port valve and toward the sample dilution junction.

12. The sample supply system according to any one of claims 1 to 11, wherein the external sample reservoir is configured as an external sample loop connected to a valve of the valve assembly.

13. The external sample reservoir is configured as an external sample loop connected to two ports of a third multi-port valve of the valve assembly. The external sample can be loaded into the external sample loop when the third multi-port valve is in the second valve position. The external sample can be supplied from the external sample loop to the sample dilution confluence section when the third multi-port valve is switched to the first valve position. The sample supply system according to any one of claims 1 to 12.

14. The valve assembly allows the first fluid pump to flow the second carrier fluid through the external sample loop when the third multi-port valve is switched to the first valve position, so that the external sample can flow from the external sample loop to the sample dilution confluence section. The sample supply system according to claim 13.

15. When the second carrier fluid flows through the external sample loop, bubbles that separate the second carrier fluid and the external sample can be introduced. The sample supply system according to claim 14.

16. The valve assembly can be configured to allow the second fluid pump to flow the diluent through the third multi-port valve to the sample dilution confluence section when the third multi-port valve is in the first valve position. The sample supply system according to any one of claims 13 to 15.

17. The valve assembly can be configured to allow the flow of the external sample along the continuous flow path from the sample source through the third multi-port valve to the analysis sample reservoir when the third multi-port valve is in the first valve position. The sample supply system according to any one of claims 13 to 16.

18. The first fluid pump and the second fluid pump flow the external sample and the diluent at a relative flow rate (v / v) within the range of 10:1 to 1:1000. The sample supply system according to any one of claims 1 to 17.

19. The first fluid pump and the second fluid pump flow the external sample and the diluent at a total flow rate of 2 ml / min to 20 ml / min. The sample supply system according to any one of claims 1 to 18.

20. The volume of the external sample reservoir is less than 20% larger than the volume of the analysis sample reservoir. The sample supply system according to any one of claims 1 to 19.

21. The sample supply system according to any one of claims 1 to 20, further comprising the sample source connected to the external sample reservoir and the analysis sample reservoir through the valve assembly.

22. The sample supply system according to claim 21, wherein the sample source is selected from the group consisting of an autosampler and an automated interface for sampling a processing fluid.

23. A spectrometer comprising the sample supply system according to any one of claims 1 to 22, and an analyzer.

24. The spectrometer according to claim 23, wherein the analyzer has a plasma source.

25. The spectrometer according to claim 23 or 24, which is either or both of an ICP-OES spectrometer and an ICP-MS spectrometer.

26. Further comprising a computing device for controlling the sample supply system to supply an external sample for spectroscopic analysis by method (a) or method (b), wherein the method (a) (i) flowing the external sample from the sample source along the continuous flow path to the analysis sample reservoir without dilution; (ii) subsequently, supplying the external sample from the analysis sample reservoir to the analyzer for spectroscopic analysis. The method (b) (i) flowing the external sample from the sample source to the external sample reservoir; (ii) subsequently, flowing the external sample from the external sample reservoir to the sample dilution junction; (iii) simultaneously flowing a diluent to the sample dilution junction to dilute the external sample to produce a diluted sample; (iv) flowing the diluted sample from the sample dilution junction to the analysis sample reservoir; (v) subsequently, supplying the diluted sample from the analysis sample reservoir to the analyzer for spectroscopic analysis. The spectrometer according to any one of claims 23 to 25.

27. The computing device supplies a first external sample for spectroscopic analysis by the method (a); determines a target dilution rate of the first external sample based on the spectroscopic analysis of the first external sample; supplies a diluted sample containing the first external sample and the diluent for spectroscopic analysis by the method (b), wherein the first fluid pump and the second fluid pump are controlled such that the first external sample and the diluent flow at a relative flow rate suitable for achieving the target dilution rate in the diluted sample. ​ The spectrometer according to claim 26. **Claim 28** A method of analysis using the spectrometer according to any one of claims 23 to 27, comprising: providing one or more external samples in a sample source for analysis; analyzing at least a first sample among the one or more external samples by a first analysis method without diluting the first sample, the first analysis method comprising: (i) flowing the first sample along the continuous flow path from the sample source to the analysis sample reservoir; and (ii) subsequently supplying the first sample from the analysis sample reservoir to the analysis device for spectroscopic analysis. A method comprising the steps of. **Claim 29** further comprising analyzing at least the first sample or the second sample among the one or more external samples by a second analysis method with inline dilution of the first sample or the second sample, wherein the second analysis method comprises: (i) flowing the first sample or the second sample from the sample source to the external sample reservoir; (ii) subsequently flowing the first sample or the second sample from the external sample reservoir to the sample dilution junction; (iii) simultaneously flowing a diluent to the sample dilution junction to dilute the first sample or the second sample to produce a diluted sample; (iv) flowing the diluted sample from the sample dilution junction to the analysis sample reservoir; (v) subsequently supplying the diluted sample from the analysis sample reservoir to the analysis device for spectroscopic analysis. including The method according to claim 28. **Claim 30** determining a target dilution ratio of the first sample based on spectroscopic analysis of the first sample obtained by the first analysis method; analyzing the first sample by the second analysis method, wherein the first fluid pump and the second fluid pump in the sample supply system are controlled such that the first sample and the diluent flow at a relative flow rate suitable for achieving the target dilution ratio in the diluted sample. The method according to claim 29, comprising the steps of. **Claim 31** providing a calibration sample having one or more analytical species of known concentration in the sample source for analysis; analyzing the calibration sample by the first analysis method and supplying the calibration sample to the analysis device for spectroscopic analysis. Analyzing the calibration sample one or more times by the second analysis method, and supplying one or more diluted calibration samples having the one or more analysis species of known concentration to the analyzer for spectroscopic analysis; The method according to claim 29, comprising:

32. Providing a plurality of external samples to the sample source for analysis; Analyzing the plurality of external samples by the first analysis method; Identifying an out-of-range sample having an analysis species concentration exceeding a predetermined maximum concentration among the plurality of external samples based on spectroscopic analysis of the plurality of external samples; When identified, analyzing the out-of-range sample by a second analysis method with inline dilution of the out-of-range sample, the second analysis method comprising: (i) flowing the out-of-range sample from the sample source to the external sample reservoir; (ii) subsequently flowing the out-of-range sample from the external sample reservoir to the sample dilution junction; (iii) simultaneously flowing a diluent to the sample dilution junction to dilute the out-of-range sample to produce a diluted sample having an analysis species concentration below the predetermined maximum concentration; (iv) flowing the diluted sample from the sample dilution junction to the analysis sample reservoir; and (v) subsequently supplying the diluted sample from the analysis sample reservoir to the analyzer for spectroscopic analysis. The method according to claim 28, comprising:

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