Polyphosphate detection device based on valve switching

Abstract

The invention relates to the technical field of polyphosphate detection, in particular to a polyphosphate detection device based on valve switching, which comprises a liquid chromatogram system provided with a public sample introduction system used for introducing a sample into the liquid chromatogram system; the valve switching unit is connected to the public sample introduction system and then used for switching different sample flow paths, and the public sample introduction system and the valve switching unit are connected and provided with at least two sample channels and two detection channels; the inductively coupled plasma mass spectrometer is used for receiving a sample signal from the detection channel of the valve switching unit and carrying out ion detection; and the control system is used for controlling coordinated operation of the liquid chromatography system, the valve switching unit and the inductively coupled plasma mass spectrometer so as to realize simultaneous detection of polyphosphate and different ions. Detection of polyphosphate and at least one kind of other ions can be achieved at the same time on the basis of the valve switching technology, other ions are detected in the polyphosphate detection process by means of the time when non-target ions flow out of the chromatographic column, and therefore the instrument utilization rate and the experiment efficiency are improved.

Description

Technical Field

[0001] The present application relates to the technical field of polyphosphate detection, and in particular to a polyphosphate detection device based on valve switching. Background Art

[0002] Polyphosphates (polyPs) are linear polymers composed of multiple phosphate groups connected by high-energy phosphate bonds. They are widely present in organisms (such as bacteria and eukaryotic cells), food additives, industrial products (such as water treatment agents) and environmental samples.

[0003] In recent years, with the advancement of analytical technology, ICP-MS coupled with liquid chromatography (LC) (LC-ICP-MS) and ion chromatography (IC) (IC-ICP-MS) can achieve the morphological distinction of polyphosphates with different polymerization degrees (such as pyrophosphate and tripolyphosphate). However, in actual operation, it is found that due to the unique chemical properties and structural characteristics of hexametaphosphoric acid, it is easy to undergo hydrolysis reaction, which prolongs the overall analysis and detection time. This situation leads to the following problems: 1. High cost: It consumes a large amount of high-purity gas (such as argon and helium), and the operating cost is high; 2. Reduced instrument stability: After long-term operation of ICP-MS, the plasma tube may have uneven energy transfer due to carbon or salt deposition, and the plasma center channel may shift, resulting in reduced instrument stability and affecting the test results; 3. Frequent maintenance: Phosphates easily form insoluble phosphate precipitates in solution, especially under high concentration or alkaline conditions. These precipitates may deposit on the nebulizer, spray chamber, spray needle and other parts of the ICP-MS, causing blockage or damage. Summary of the invention

[0004] Conventional ICP-MS coupled with liquid chromatography (LC) (LC-ICP-MS) and ion chromatography (IC) (IC-ICP-MS) have a long overall analysis time due to the easy hydrolysis of hexametaphosphoric acid. To solve this problem, the present invention provides a polyphosphate detection device based on valve switching, which fully utilizes the detection time of polyphosphate by switching the flow path selection valve, and achieves the purpose of detecting polyphosphate and at least one other ion, specifically comprising: The system of the present invention adopts a valve switching device, which can switch different sample flow paths to the mass spectrometer injection port after the liquid chromatography column.

[0005] The present invention has the following advantages: 1. Based on valve switching, polyphosphate and at least one other ion can be detected simultaneously, making full use of the time for non-target ions to completely flow out of the chromatographic column during the polyphosphate detection process, thereby improving the utilization rate of the instrument; 2. The detection time of one ion can detect multiple other ions at the same time, saving experimental resources and improving experimental efficiency; 3. Phosphates easily form insoluble phosphate precipitates in solution, especially under high concentration or alkaline conditions. These precipitates may be deposited on the atomizer, spray chamber, spray needle and other parts of the ICP-MS, causing blockage or damage. The device of the present invention can prevent the ICP-MS from being exposed to phosphate for a long time, causing instrument loss. Technical Solution

[0006] The present invention provides a polyphosphate detection device based on valve switching, comprising: Liquid chromatography system (LC System): used to separate components in a sample.

[0007] Valve Switching Unit: connected between the common injection system and the ICP-MS injection port, with at least two sample channels and two detection channels. The valve switching unit can switch different sample channels to their respective detection channels in sequence according to a preset program or user instructions, so that different sample eluents enter the ICP-MS. The valve switching unit is at least two multi-way valves. The valve switching unit can use a multi-way valve, such as a six-way valve or a valve with more than one way.

[0008] Inductively coupled plasma mass spectrometer (ICP-MS): used to detect sample signals introduced through a valve switching unit after liquid chromatography separation.

[0009] Sample Channels: Each sample channel is connected to a sample flow path and is used to introduce different samples.

[0010] Control System: used to control the coordinated operation of the liquid chromatography system, valve switching unit and ICP-MS.

[0011] The present invention also provides a detection strategy based on the above-mentioned valve switching-based polyphosphate detection device, comprising the following steps: Sample separation: a) The liquid chromatography system is running and the sample is separated. b) Valve switching: The valve switching unit switches the eluent of the polyphosphate sample channel to the detection channel leading to the ICP-MS according to the preset program or user instructions. During the mass spectrometry detection process, when the polyphosphate sample is still eluting and detecting, the valve switching unit can switch to the next sample channel in advance to start the injection and separation of the next sample, so as to make full use of the sample analysis time. c) Mass spectrometry detection: ICP-MS receives the eluent from the detection channel of the valve switching unit and performs data acquisition. The control system sets the detection time of polyphosphate and other ions and controls the operation of the system through the software interface. d) Data processing: The data processing software processes and analyzes the data of each sample according to the set detection time.

[0012] At this time, the overall detection time is the detection time of the polyphosphate sample. The time when the next sample starts to be detected is the time before the peak of hexametaphosphoric acid and its hydrolysis products emerge. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1-5 This is a structural diagram of a valve switching unit of a polyphosphate detection device based on valve switching in this embodiment; Figure 6 This is a chromatogram showing the analysis and detection of polyphosphate and inorganic selenium by the polyphosphate detection device based on valve switching in this embodiment; The symbols in the figure refer to: A-injection six-way valve, 1 / 2 / 3 / 4 / 5 / 6-injection six-way valve first to sixth ports; B-first elution valve, B1 / B2 / B3 / B4 / B5 / B6-first to sixth ports of the first elution valve; C-second elution valve, C1 / C2 / C3 / C4 / C5 / C6-first to sixth ports of the second elution valve; 11-first infusion pump; 12-quantitative loop; 13-second infusion pump; 14-first analytical column; 15-three-way valve; 16-third infusion pump; 17-second analytical column. DETAILED DESCRIPTION

[0014] The technical solution of the present invention is further described below in conjunction with a specific embodiment.

[0015] System construction: ICP-MS; Liquid chromatography system: public injection system (injection six-way valve A), first analytical column 14 and second analytical column 17; The six ports of the injection six-way valve A are connected to: Port 1: first infusion pump 11; Port 2: Second port B2 of the first elution six-way valve.

[0016] Port 3: one end of the quantitative loop 12; Port 4: injection needle; Port 5: plunger pump; Port 6: one end of the quantitative loop 12.

[0017] Valve switching unit: includes two six-way valves, wherein the six ports of the first elution six-way valve are respectively connected to: Port 1: inlet end of the first analytical column 14; Port 2: injection six-way valve (A) second port 2; Port 3: the sixth port C6 of the second elution valve C; Port 4: outlet end of the first analytical column 14; Port 5: one end of the three-way valve 15 is connected to the ICP-MS detector; Port 6: Second infusion pump 13.

[0018] The six ports of the second elution six-way valve are connected respectively: Port 1: inlet end of the second analytical column 17; Port 2: third infusion pump 16; Port 3: one end of the three-way valve 15 is connected to the ICP-MS detector; Port 4: outlet end of the second analytical column 17; Port 5: waste liquid outlet; Port 6: The third port B3 of the first elution valve B.

[0019] Use computer and control software to control the whole system.

[0020] Detection strategy: like Figure 1 , Stage I: polyphosphate sample injection; like Figure 2 , Stage II: Switching the injection six-way valve A to allow the polyphosphate sample of step I to enter the first analytical column 14 for separation; like Figure 3 , Stage III: Switch the injection flow valve, the first elution valve B and the second elution valve C to allow the sample separated by the analytical column in step II to enter the ICP-MS detection, and inject the inorganic selenium sample at the same time; like Figure 4 , Stage IV: Switch the injection six-way valve A to allow the sample injected in step III to enter the second analytical column 17 for separation; like Figure 5 , Stage V: Switch the injection six-way valve A, the first elution valve B and the second elution valve C to allow the sample separated by the analytical column in step IV to enter the ICP-MS detection.

[0021] like Figure 6 As shown in the figure, it is a chromatogram detected by the valve switching-based polyphosphate detection device of the present invention, a is the conventional ICP-MS combined with ion chromatography (IC) (IC-ICP-MS) to analyze and detect polyphosphates (phosphoric acid, pyrophosphate, trimetaphosphate, tripolyphosphate and hexametaphosphate) in the sample. It can be seen that the whole analysis process takes 22 minutes in total. From about 12 minutes onwards, the latter half is the peak of hexametaphosphate and its hydrolysis products. Therefore, the device is switched at about 12 minutes. Figure 6 The dotted lines shown in b and c are the valve switching time. Polyphosphate is detected before switching, and other ions are analyzed and detected after switching. This embodiment is an example of inorganic selenium detection. In this embodiment, the same detection time realizes the analysis and detection of two ions.

[0022] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A polyphosphate detection device based on valve switching, characterized in that: include: The liquid chromatography system is provided with a common injection system; a valve switching unit is connected to the common injection system and is used to switch different sample flow paths; the common injection system and the valve switching unit are connected to have at least two sample channels and two detection channels; An inductively coupled plasma mass spectrometer, used to receive a sample signal from a detection channel of a valve switching unit and perform ion detection; and a control system for controlling the coordinated operation of a liquid chromatography system, a valve switching unit and an inductively coupled plasma mass spectrometer to achieve simultaneous detection of polyphosphate and different ions.

2. The polyphosphate detection device based on valve switching according to claim 1, characterized in that: The valve switching unit is at least two multi-way valves.

3. The polyphosphate detection device based on valve switching according to claim 2, characterized in that: The valve switching unit is a six-way valve or a valve with more than one way.

4. The polyphosphate detection device based on valve switching according to claim 1, characterized in that: The liquid chromatography system comprises at least two analytical columns for separating components in different samples.

5. A detection strategy based on the valve switching-based polyphosphate detection device according to claim 1, characterized in that: The following steps are involved: a) The liquid chromatography system separates the polyphosphate sample; b) The valve switching unit switches the flow path, and the mass spectrometer receives and detects the signal of the polyphosphate sample within the set detection time; c) The liquid chromatography system separates other samples except polyphosphate; d) The valve switching unit switches the flow path before the non-target ion peak time, and the mass spectrometer receives and detects the signals of other samples within the set detection time.

6. The detection strategy according to claim 5, characterized in that: The overall detection time is the detection time of the polyphosphate sample.

7. The detection strategy according to claim 5, characterized in that: The next sample starts to be detected before the non-target ion peak time.

8. The polyphosphate detection device based on valve switching according to claim 1, characterized in that: The control system realizes the setting of the detection time of polyphosphate and other ions and the control of the system operation through a software interface.

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