Dual detection colorimeter optical measurement

Abstract

An embodiment provides a method, for measuring a reagent and a parameter of an aqueous sample, including: introducing an aqueous sample and reagents into a measurement device comprising at least one light source, at least one wavelength, control device, at least one detector, and a measurement cell; measuring, using the at least one detector, a first value of absorbance at a first wavelength correlated to a regent concentration; measuring, using the at least one detector, a second value of absorbance at a second wavelength correlated to a parameter concentration; and correcting the second value of absorbance based upon the first value of absorbance. Other aspects are described and claimed.

Description

DUAL DETECTION COLORIMETER OPTICAL MEASUREMENTCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Patent Application Serial No, 63 / 688,842, filed on August 29, 2024, and entitled “DUAL DETECTION COLORIMETER OPTICAL MEASUREMENT,” the contents of which are incorporated by reference herein.FIELD

[0002] This application relates generally to optical measurement of an analyte in a solution, and, more particularly, to measurement of a reagent concentration in a solution during an optical measurement.BACKGROUND

[0003] Ensuring water quality is critical in a number of industries such as pharmaceuticals and other manufacturing fields. Additionally, ensuring water quality is critical to the health and well-being of humans, animals, and plants which are reliant on the water for survival. An analyte of the water may be measured as an indication of the quali ty of the sample. Measurement may allow for identification or computation of other parameters of the sample, for example, buffering capacity, a component of the sample, orP2024-0024-W001(27441 ,695_PCT)the like, which allows for identifying the overall quality of the water. The number of different parameters that can be tested for is large, with most parameters requiring the use of a different chemistry or test instrument for testing. One method to measure a component or analyte of the sample is to use a colorimeter or other optical based measurement instrument.

[0004] A colorimeter measures the absorbance at a wavelength of light through a sample in a sample cuvette or vial. A colorimeter determines the concentration of a component in a liquid sample within a sample cuvette by projecting a light beam into the liquid sample within the cuvette. An absorbance for the given wavelength may then be measured. A concentration of the component of the sample may be measured as proportional to the measured absorbance. Different wavelengths may be selected based upon the species to be measured and specific applications.

[0005] A colorimeter generates light with a source, may pass the light through an aperture to a lens and / or a color filter, and then into the sample. The wavelength of light may be selected for a given application. The light then passes through a cuvette or sample cell / chamber. After passing through a cuvette or sample cell / chaniber the light may strike a photocell or detector for a measurement of absorbance in the form of an output. The absorbance may be correlated to a concentration of the species to be measured in a sample.BRIEF SUMMARY

[0006] In summary, one embodiment provides a method for measuring a reagent and a parameter of an aqueous sample, comprising: introducing an aqueous sample and reagents into a measurement device comprising at least one light source, at least one wavelength control device, at least one detector, and a measurement cell; measuring, using the at least one detector, a first value of absorbance at a first wavelength correlated to a regent concentration; measuring, using the at least one detector, a second value of absorbance at a second wavelength correlated to a parameter concentration; and correcting the second value of absorbance based upon the first value of absorbance,

[0007] Another embodiment provides a device for measuring a reagent and a parameter of an aqueous sample, comprising: at least one light source; at least one device to control a wavelength; at least one detector; a measurement cell; a processor: and a memory device that stores instructions executable by the processor to: measure, using the at least one detector, a first value of absorbance at a first wavelength correlated to a regent concentration; measure, using the at least one detector, a second value of absorbance at a second wavelength correlated to a parameter concentration; and correct the second value of absorbance based upon the first value of absorbance.

[0008] A further embodiment provides a product for measuring a reagent and a parameter of an aqueous sample, comprising: at least one light source; at least onedevice to control a wavelength; at least one detector; a measurement cell; a processor; and a storage device having code stored therewith, the code being executable by the processor and comprising: code that measures, using the at least one detector, a first value of absorbance at a first wavelength correlated to a regent concentration; code that measures, using the at least one detector, a second value of absorbance at a second wavelength correlated to a parameter concentration; and code that corrects the second value of absorbance based upon the first value of absorbance.

[0009] The foregoing is a summary and thus may contain simplifications, generalizations, and omissions of detail; consequently, those skilled in the art will appreciate that the summary is illustrative only and is not intended to be in any way limiting.

[0010] For a beter understanding of the embodiments, together with other and further features and advantages thereof, reference is made to the following description, taken in conjunction with the accompanying drawings. The scope of the invention will be pointed out in the appended claims,BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0011] FIG. 1 illustrates a diagram of a method for measuring a reagent concentration by adding a dye to the reagent at a known concentration then measuring it in a sample using an optical method.

[0012] FIG. 2 illustrates a diagram of a method for measuring reagent concentration using an inflection or isosbestic point to measure a dispensed reagent volume using an optical method.

[0013] FIG. 3 illustrates a diagram of a method for determining a wavelength to measure a dispensed reagent volume at a non reactive or less reactive wavelength using an optical method.

[0014] FIG. 4 illustrates an example dual detector colorimeter device with a beam splitter.

[0015] FIG. 5 illustrates an example dual detector colorimeter device with parallel light paths.

[0016] FIG. 6 illustrates an example dual detector colorimeter device with intersecting light paths.

[0017] FIG. 7 illustrates an example dual detector colorimeter device with converging light paths.

[0018] FIG. 8 illustrates an example dual detector colorimeter device with diverging light paths.

[0019] FIG. 9 illustrates example data of optical measurement over wavelength for measuring a parameter and reagent of a sample using alkalinity standards and changing regent concentration

[0020] FIG. 10 illustrates an example volume correction with a dual wavelength colorimeter using two different food colors in varying ratios and sample volumes.

[0021] FIG . 11 illustrates the application of a correction equation to the data from FIG. 10 demonstrating how the variability in sample and food coloring concentration is corrected.

[0022] FIG. 12 illustrates flow diagram of measuring a reagent concentration and an analyte in a sample using optical measurement.

[0023] FIG. 13 illustrates an example of computer circuitry.DETAILED DESCRIPTION

[0024] It will be readily understood that the components of the embodiments, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations in addition to the described example embodiments. Thus, the following more detailed description of the example embodiments, as represented in the figures, is not intended to limit the scope of the embodiments, as claimed, but is merely representative of example embodiments.

[0025] Reference throughout this specification to “one embodiment” or "an embodiment” (or the like) means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” or the like in various places throughout this specification are not necessarily all referring to the same embodiment.

[0026] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that the various embodiments can be practiced without one or more of the specific details, or with other methods, components, materials, et cetera. In other instances, well-known structures,materials, or operations are not shown or described in detail. The following description is intended only by way of example, and simply illustrates certain example embodiments.

[0027] Conventional methods and systems for measuring absorbance using a colorimeter includes the colorimeter utilizing a light source to generate a light beam, which may be a beam of a given wavelength. A sample of fluid may be placed in a cuvette, sample cell, sample vessel, or the like for measurement of a component in the sample. The measurement beam may be axially directed into a sample cell. The sample cell may have a window to allow the passage of light through the sample cell so that the light, beam of the colorimeter can infiltrate, and pass through the sample cell. In some embodiments of a colorimeter, a sample cell may be a one-time use vessel.

[0028] In an embodiment, a colorimetric measurement may use a calibration curve or a default calibration curve eliminating a need to calibrate an instrument prior to a measurement. Alternatively, colorimetric measurement begins with a calibration of the colorimeter using standard solutions of the known solute or component concentration to be determined. Then a light ray is directed in the direction of the solution. The light ray may be a wide band light filtering off a specific wavelength after passage through a sample. The light may pass through a series of different lenses and filters. The colored light passing through the lenses and the filter may be split into beams of light of different wavelengths allowing only the required wavelength to passand reach the cuvette of the standard test solution or the detector(s). The beam of light reaching the cuvette is transmitted, reflected, and absorbed by the solution. This transmitted ray falls on the photodetector system which measures the intensity of transmitted light. The detected ray is converted into an electrical signal, and a galvanometer may convert the signal and a display allows a visual reading of the result using formula to determine substance concentration in test solution.

[0029] Optical measurement instruments, such as a colorimeter or the like, pass light through a sample for measurement. A specific wavelength may be used for different analytes. A measurement may be taken prior to and after a colorimetric reaction to detect an analyte. The measurement of light passing through after the colorimetric reaction may be due to the reaction of the analyte with the chemistry of the colorimetric reaction. However, errors may be introduced into a colorimetric measurement. Reducing these errors may improve accuracy, improved performance of a test, and / or reduce instrument, labor, and reagent costs,

[0030] For example, a measurement of a reagent concentration may reduce uncertainty or error by reducing error from the following sources; First, a colorimetric measurement may have a variability in a reagent pumping or dispensing volume. Second, a colorimeter test sample size may be variable. Third, properties of a fluid to be measured may have a different surface tension, weir breakover, and / or samplewicking. Fourth, there may be different zero or offset corrections tor a reagent with an offset at a parameter measurement wavelength. Fifth, the sample may contain or generate bubbles that change the sample volume

[0031] Accordingly, the systems and methods described herein provide a technique for analyte or parameter measurement in a sample. In an embodiment, an accuracy of a parameter concentration measurement may be increased by measuring a reagent concentration within the sample. In other words, the parameter may be a component of a sample to be measured, and the reagent concentration may be from a component added to the reagent to provide a colorimetric measurement such as a dye for example. In an embodiment, the measurement of the parameter and the measurement of the reagent concentration may be at two different wavelengths. For example, the method and device may measure a reagent concentration at one wavelength, and measure a parameter at another wavelength. The two measurements may allow a correction for determination of a volume or amount of reagent or a parameter.

[0032] The illustrated example embodiments will be best understood by reference to the figures. The following description is intended only by way of example, and simply illustrates certain example embodiments.

[0033] Referring to FIG. 1. in an embodiment, a method for colorimetric measurement of a reagent concentration and a parameter is illustrated. In an embodiment, measuring a second wavelength with the colorimeter may measure a reagent or dye concentration at one wavelength and measure a parameter of a sample with another wavelength. A parameter concentration may be calculated using the reagent concentration leading to a more accurate colorimetric measurement. For example, an inert dye may be added to the reagents which responds at a wavelength different from a wavelength for the parameter. A measurement from the colorimeter may be observed or recorded for an intensity of the reagent at the reagent wavelength which is different from the measured wavelength of the parameter. The illustrated example, shows separate dye (reagent) measurement wavelength and the associated parameter wavelength response curve from the parameter concentration measurement wavelength with a high / low parameter concentration. Sample data from a sample plotting light output over wavelength is illustrated. The light output may be an electrical signal from an optical sensor. The illustrated curves are exemplars, as the shape of these curves may vary based upon parameter concen tration, type of reagent, reaction condition s, or the like. For example, a measured curve or dye curve may have a different shape, be in a different location (ex. dye is at a higher wavelength) or may be inverted.

[0034] Referring to FIG. 2. in an embodiment, a method for colorimetric measurement of a reagent and a parameter using an inflection point is illustrated. In an embodiment, some reagents or dyes may have a wavelength inflection point or valleys in which the reagent does not react. This inflection point may be referred to as an isosbestic point. Measuring an intensity of this inflection point may allow for a calculation of a dispensed reagent volume or reagent concentration within the sample. Another measurement for a parameter concentration may be made at a point in which the wavelength reaches a peak or valley. The parameter measurement may also use the determined reagent concentration or reagent dispense volume for the parameter concentration calculation. The illustrated curves are exemplars, as the shape of these curves may vary based upon parameter concentration, type of reagent, reaction conditions, or the like. For example, a measured curve may have a positive slope, negative slope, varying slope, or the like before or after an inflection point. Illustrated curves demonstrate a low, medium, and high parameter concentration. In an embodiment, the left box denotes a point at which an inflection occurs and the reagent does not react, and a reagent concentration may be measured. In an embodiment, the right box denotes a point at which a low, medium, or high example parameter to be measured in a sample is measured.

[0035] Referring to FIG. 3. in an embodiment, a method for measuring a reagent concentration and a parameter is illustrated. In an embodiment, a reagent may generate an intensity using colorimetric measurement at a wavelength, but the reagent does not react with a parameter at a second wavelength. In an embodiment, the wavelength at which a reagent concentration may be measured at which the reagent does not react with a parameter is illustrated by the box on the left. In an embodiment, a parameter, or component of a sample, to be measured may be measured using colorimetric methods at another wavelength denoted by the box on the right. The three curves illustrate a high, medium, and low parameter concentration. The illustrated curves are exemplars and the shape, slope, and non reactive points may be different with different samples, reagents, parameters, or the like.

[0036] Referring to FIG. 4, in an embodiment, a device for measuring a reagent concentration and a parameter of a sample using colorimetric methods is illustrated. Colorimetric measurement uses a light ray directed toward a sample. The light may pass through a series of different lenses and / or filters. The ray of light passes through the lenses and sample and then is split before passing through fillers to isolate a beam of light into specific wavelengths that are then measured. The beam of light reaching the cuvette is transmitted, reflected, and absorbed by the solution. In an embodiment, the light sources, such as an LED (light emitting diode), may emit lightthrough a colorimeter cell. The light may then reach a beam splitter. The beam splitter directs the light in at least two directions. Each light path may have a wavelength filter and associated detector for a given wavelength. For any of the embodiments, a wavelength or wavelength control of light may be accomplished using a specific LED light source, a filter or wavelength filter, or a combination of the two. In the example, the beam spliter allows one wavelength to pass straight through and another wavelength of light to turn about 90 degrees. Other angles are disclosed and contemplated with a 90 degree angle used as an example. In the example, the wavelength filter and detector, and another wavelength filter and detector may each measure a reagent or a parameter. In other words, each filter and detector measures one of each of the reagent and parameter. In an embodiment, this may be referred to as a beam splitter configuration for a colorimeter measurement device.

[0037] Referring to FIG. 5, in an embodiment, another device for measuring a reagent concentration and a parameter of a sample using colorimetric methods is illustrated. In an embodiment, this configuration may be referred to as a parallel, or substantially parallel, configuration. In an embodiment, there may be more than one, but preferably two light sources, such as LED’s. The light paths travels through the colorimeter cell and without a beam spliter, each of the light rays may pass thru a wavelength filter and then falls upon a detector, In the example, the wavelength filter anddetector, and another wavelength filter and detector may each measure a reagent concentration or a parameter. In other words, each filter and detector measures one of each of the reagent concentration and parameter. The LED light sources and associated filter / detector may measure at discrete time points independent of one another or simultaneously. In this embodiment the separate light sources may emit at different wavelengths and wavelength filters may not be required.

[0038] Referring to FIG. 6, in an embodiment, a further device for measuring a reagent concentration and a parameter of a sample using colorimetric methods is illustrated. In an embodiment, this configuration may be referred to as an intersecting configuration. In an embodiment, there may be more than one, but preferably two light sources, such as LED's. The light paths travels through the colorimeter cell and without a beam splitter, each of the light rays may travel through a wavelength filter and fall upon a detector. In the example, the wavelength filter and detector, and another wavelength filter and detector may each measure a reagent concentration or a parameter. In other words, each filter and detector measures one of each of the reagent and parameter. The light emitted from the LED intersect in an area of the colorimeter cell. The LED light sources and associated filter / detector may measure at discrete time points independent of one another or simultaneously. In this embodiment the light sources may be of different wavelengths and the wavelength filters may not be required.

[0039] Referring to FIG. 7. in an embodiment, a further device for measuring a reagent concentration and a parameter of a sample using colorimetric methods is illustrated. In an embodiment, this configuration may be referred to as a convergent configuration. In an embodiment, the device may have multiple light sources, preferably two. The light from the multiple LEDs travels through the colorimeter cell and converge upon a single detector. The detector is capable of measuring the wavelengths from the multiple LED light sources. Each of the light sources may produce a wavelength for measurement for a reagent concentration or parameter In a sample. The LED’s may produce light simultaneously or sequentially over time. In this embodiment there may also be wavelength filters to limit the light wavelength from each separate source.

[0040] Referring to FIG. 8, in an embodiment, a further device for measuring a reagent concentration and a parameter of a sample using colorimetric methods is illustrated. In an embodiment, this configuration may be referred to as a divergent configuration. In an embodiment, the device may have a single light source capable of producing a wavelength to measure a reagent concentration and a parameter of a sample. The light from the LED travels through the colorimeter cell and diverge upon two or more wavelength filters and detectors. Each detector is capable of measuring the wavelength for a reagent concentration or a parameter wavelength measurement. The detectors may measure light simultaneously or sequentially over time.

[0041] Referring to FIG. 9. in an embodiment, an example data set from a dual detection colorimeter method is illustrated. A wavelength response using alkalinity standards and changing reagent concentration is illustrated. In an embodiment, a component of the reagent(s) may be bromocresol green, as part of a reagent for alkalinity measurement in an instrument. This reagent has an isosbestic point (about 510 ran) and a wavelength where it develops color (about 615 am). The isosbestic point may be defined as a wavelength at which the reagent does not react with a parameter at that wavelength. The example uses 3 different sample concentrations with 2 different reagent concentrations. For example, an alkalinity standard may be a blank, 52 milligrams per liter (mg / L), or 100 mg / L. For example, the reagent concentrations may be 200 microliters (pL) or 250 pL. As in previous examples, an example box is illustrated for a reagent and parameter measurement in a sample.

[0042] Referring to FIG. 10, in an embodiment, another example data set from a dual detection colorimeter method is illustrated. For example, the test is conducted with 2 dyes. In the example, the volume of one dye was constant (blue), and then the concentration of the second dye (yellow) is varied, and the sample volume is also varied. Data from one set of sample volumes is used to generate a “calibration curve” for the reagent. Referring to FIG. 11, in an embodiment, the data from FIG. 10 are corrected as described. Using the blue dye to correct for the varying sample volume brought all of theyellow dye measurements into groupings that corresponded to the yellow dye volume. The method and technique reduces the error in the calculated variable dye (yellow) volume in the sample. Dye volume is used for the correction, but if the calibration curve were based on parameter concentration (mg / L) the outcome is similar, and reduces the error in calculated parameter concentration.

[0043] Referring to FIG, 12, an embodiment may measure a reagent and / or parameter of a sample using colorimetric methods. In an embodiment, the method or system may determine a concentration of amount of a reagent, a parameter, or a volume of a sample or reagent. At 1201, in an embodiment, a sample may be introduced into a measurement chamber or region. The measurement chamber may comprise an optical path from at least one light source to at least one optical sensor or detector. The light path may pass through one or more filters. The light path may pass through one or more beam splitters. The sample may be placed or introduced into a chamber manually by a user or using a mechanical means, tor example, gravity flow, a pump, pressure, fluid flow, or the like. For example, a water sample for analyte measurement may be introduced to a chamber by a pump. In an embodiment, there may be one or more chambers in which the one or more method steps may be performed. In an embodiment, valves or the like may control the influx and efflux of the aqueous solution into or out of the one or more chambers, if present. Once the samp le is introduced to the measurementsystem, the system may collect optical data from an optical sensor to determine the presence of adequate sample and / or an analyte in the sample.

[0044] Also at 1201, one or more reagent(s) are added to the sample. The reagent(s) may be added manually, with a pump, with valves, into the sample stream flowing into the measurement device, or with other methods as defined by the measurement process. These reagent(s) may react with the sample to allow the measurement of the parameter concentration. The reagents may also have properties that allow the reagent concentration to be measured to correct for variability in the reagent concentration within the sample during the measurement cycle,

[0045] At 1202, in an embodiment, the method and system may measure a first value of absorbance at a first wavelength. The first measurement may be correlated to a reagent concentration, an amount of reagent, a volume of reagent, or the like. In an embodiment, a reagents or dye may have a wavelength inflection point or valleys in which the reagent does not react. This inflection point may be referred to as an isosbestic point. Measuring an intensity of this inflection point may allow for a calculation of a dispensed reagent volume of reagent volume. Another measurement for a reagent concentration may be made at a point in which the wavelength response reaches a peak or valley. The wavelength measurement may also use the determined reagent concentration of reagent dispense volume for the calculation. The first measurement may be stored in adatabase, provided as a readout, used in a calculation, or the like. The first wavelength of Light may be generated by a light source, travel through a measurement chamber, travel through a filter and / or beam splitter, tall upon a detector, or any combination thereof.

[0046] At 1203, in an embodiment, the method and system may measure a second value of absorbance at a second wavelength. The second measurement may be correlated to a parameter concentration, an amount of a parameter, a volume of parameter, or the like. The second measurement may be stored in a database, provided as a readout, used in a calculation, or the like. The first wavelength of fight may be generated by a light source, travel through a measurement chamber, travel through a filter and / or beam splitter, fall upon a detector, or any combination thereof.

[0047] In an embodiment, at 1204, the method and system may correct the second measurement based upon the first measure. For example, a parameter measurement may be compared to a reagent measurement. In an embodiment, the correction may determine a volume or amount of a reagent. The reagent may be dispensed into the measurement chamber. Colorimetric measurements may suffer from measurement errors due to inaccurate dispensing of a reagent, dye, or the like. The methods or system may correct for a measured, real-time, amount of volume of dispensed reagent. In other words, an amount of volume of a dispensed reagent may add variability to a measurement of a parameter. In an embodiment, a volume of dispense reagent for agiven sample allows for a more accurate measurement of a parameter in the sample or aqueous sample.

[0048] If, however, the volume, amount, or concentration of the reagent and / or parameter to be corrected and accurately measured at 1204, the system, at 1205, may output a concentration or volume of a reagent or parameter, an optical reading of light throughput, or the like of the sample. In this embodiment, at 1206, an output may be in the form of a display, storing the data to a memory device, sending the output through a connected or wireless system, printing the output, or the like. The system may be automated, meaning the system may automatically output the measurement, or optical reading. The system may also have associated alarms, limits, or predetermined thresholds. For example, if a measured value reaches a threshold, the system may trigger an alarm, alert the system / personnel to a fault, alter the flow of the sample solution, or the like. Data may be analyzed in real-time, stored for later use, or any combination thereof.

[0049] The various embodiments described herein thus represent a technical improvement to conventional methods and instruments for optical measurement of an analyte in a sample. This is in contrast to conventional methods with limitations mentioned above. Such techniques provide a better method for optical measurement of an analyte in a sample.

[0050] While various other circuits, circuitry or components may be utilized in information handling devices, with regard to an instrument for analyte measurement according to any one of the various embodiments described herein, an example is illustrated in FIG. 13. Device circuitry 10' may include a measurement system on a chip design found, for example, a particular computing platform (e.g., mobile computing, desktop computing, etc. ) Software and processors) are combined in a single chip 1 1 '. Processors comprise internal arithmetic units, registers, cache memory, busses, I / O ports, etc., as is well known in the art. Internal busses and the like depend on different vendors, but essentially all the peripheral devices (12’) may attach to a single chip 11 '. The circuitry 10' combines the processor, memory control, and I / O controller hub all into a single chip 11 Also, systems 1 O' of this type do not typically use SATA or PCI or LPC. Common interfaces, for example, include SDIO and I2C.

[0051] There are power management chip(s) 13', e.g., a battery management unit, BMU, which manage power as supplied, for example, via a rechargeable battery 14', which may be recharged by a connection to a power source (not shown). In at least one design, a single chip, such as 11 ", is used to supply BIOS like functionality and DRAM memory.

[0052] System 10' typically includes one or more of a WWAN transceiver15' and a WLAN transceiver 16' for connecting to various networks, such astelecommunications networks and wireless Internet devices, e.g., access points. Additionally, devices 12' are commonly included, e.g., a transmit and receive antenna, oscillators, PLLs, etc. System 10' includes input / output devices 17' for data input and display / rendering (e.g., a computing location located away ftom the single beam system that is easily accessible by a user). System 10' also typically includes various memory devices, for example flash memory 18' and SDRAM 19'.

[0053] It can be appreciated from the foregoing that electronic components of one or more systems or devices may include, but are not limited to, at least one processing unit, a memory, and a communication bus or communication means that couples various components including the memory to the processing unit(s). A system or device may include or have access to a variety of device readable media. System memory may include device readable storage media in the form of volatile and / or nonvolatile memory such as read only memory (ROM) and / or random access memory (RAM). By way of example, and not limitation, system memory may also include an operating system, application programs, other program modules, and program data. The disclosed system may be used in an embodiment of an instrument for analyte measurement.

[0054] As will be appreciated by one skilled in the art, various aspects may be embodied as a system, method or device program product. Accordingly, aspectsmay take the form of an entirely hardware embodiment or an embodiment including software that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects may take the form of a device program product embodied in one or more device readable medium(s) having device readable program code embodied therewith.

[0055] It should be noted that the various functions described herein may be implemented using instructions stored on a device readable storage medium such as a non-signal storage device, where the instructions are executed by a processor. In the context of this document, a storage device is not a signal and “non-transitory” includes all media except signal media.

[0056] Program code for carrying out operations may be written in any combination of one or more programming languages. The program code may execute entirely on a single device, partly on a single device, as a stand-alone software package, partly on single device and partly on another device, or entirely on the other device. In some cases, the devices may be connected through any type of connection or network, including a local area network (LAN) or a wide area network ( WAN), or the connection may be made through other devices (for example, through the Internet using an Internet Service Provider), through wireless connections, e.g., near-field communication, or through a hard wire connection, such as over a USB connection.

[0057] Example embodiments are described herein with reference to the figures, which illustrate example methods, devices and products according to various example embodiments. It will be understood that the actions and functionality may be implemented at least in part by program instructions. These program instructions may be provided to a processor of a device, e.g., a measurement device such as illustrated, or other programmable data processing device to produce a machine, such that the instructions, which execute via a processor of the device, implement the functions / acts specified.

[0058] It is noted that the values provided herein are to be construed to include equi valent values as indicated by use of the term “about” The equivalent values will be evident to those having ordinary skill in the art, but at the least include values obtained by ordinary rounding of the last significant digit.

[0059] This disclosure has been presented for purposes of illustration and description but is not intended to be exhaustive or limiting. Many modifications and variations will be apparent to those of ordinary skill in the art. The example embodiments were chosen and described in order to explain principles and practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.

[0060] Thus, although illustrative example embodiments have been described herein with reference to the accompanying figures, it is to be understood that this description is not limiting and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the disclosure.

Claims

CLAIMSWhat is claimed is:

1. A method for measuring a reagent and a parameter of an aqueous sample, comprising; introducing an aqueous sample and reagents into a measurement device comprising at least one light source, at least one wavelength control device, at least one detector, and a measurement cell; measuring, using the at least one detector, a first value of absorbance at a first wavelength correlated to a regent concentration; measuring, using the at least one detector, a second value of absorbance at a second wavelength correlated to a parameter concentration; and correcting the second value of absorbance based upon the first value of absorbance.

2. The method of claim 1, wherein the correcting comprises adjusting for a dispensed volume of the reagent.

3. The method of claim 1, wherein the measurement at an isosbestic point comprises a wavelength at which the reagent does not react with a parameter at that wavelength.

4. The method of claim 1, wherein a calculated volume of a variable reagent based on the intensity of a fixed dye corrects for an error generated by a change in sample volume and reagent dispensing.

5. The method of claim 1 , wherein a light path of the first wavelength and a light path of the second wavelength pass through a beam splitter each taking a different path thereafter.

6. The method of claim 1, wherein a light path of the first wavelength and a light path of the second wavelength are parallel to one another.

7. The method of claim 1 , wherein a light path of the first wavelength and a fight path of the second wavelength intersect and cross one another.

8. The method of claim 1, wherein a light path of the first wavelength and a light path of the second wavelength converge upon one another.

9. The method of claim 1, wherein a light path of the first wavelength and a light path of the second wavelength diverge from one another.

10. The method of claim 1, wherein the parameter is a component of the aqueous sample to be measured.

11. A device for measuring a reagent and a parameter of an aqueous sample, comprising: at least one light source; at least one device to control a wavelength; at least one detector; a measurement cell; a processor; and a memory device that stores instructions executable by the processor to: measure, using the at least one detector, a first value of absorbance at a first wavelength correlated to a regent concentration; measure, using the at least one detector, a second value of absorbance at a second wavelength correlated to a parameter concentration; and correct the second value of absorbance based upon the first value of absorbance,12, The device of claim 11, wherein the correcting comprises adjusting for a dispensed volume of the reagent.

13. The device of claim 11, wherein the measurement at an isosbestic point comprises a wavelength at which the reagent does not react with a parameter at that wavelength.

14. The device of claim 1 1 , wherein a calculated volume of a variable reagent based on the intensity of a fixed dye corrects for an error generated by a change in sample volume and reagent dispensing.

15. The device of claim 1 1 , wherein a light path of the first wavelength and a light path of the second wavelength pass through a beam splitter each taking a different path thereafter.

16. The device of claim 1.1, wherein a light path of the first wavelength and a light path of the second wavelength are parallel to one another.

17. The device of claim 11, wherein a light path of the first wavelength and a light path of the second wavelength intersect and cross one another.

18. The device of claim 11, wherein a light path of the first wavelength and a light path of the second wavelength converge upon one another.

19. The device of claim 1 1, wherein a light path of the first wavelength and a light path of the second wavelength diverge from one another.

20. A product for measuring a reagent and a parameter of an aqueous sample, comprising: at least one light source; at least one device to control a wavelength; at least one detector; a measurement cell; a processor; and a storage device having code stored therewith, the code being executable by the processor and comprising: code that measures, using the at least one detector, a first value of absorbance at a first wavelength correlated to a regent concentration; code that measures, using the at least one detector, a second value of absorbance at a second wavelength correlated to a parameter concentration; and code that corrects the second value of absorbance based upon the first value of absorbance.

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