Method of determining analyte concentration in a sample using infrared transmission data
First Claim
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1. A method of determining an analyte concentration in a sample, the sample comprising the analyte and a substance, the method comprising:
- providing absorption data of the sample;
providing reference absorption data of the substance;
calculating a substance contribution of the absorption data, wherein calculating the substance contribution comprises scaling the reference absorption data by multiplying the reference absorption data by a scaling factor, the scaling factor allowing for calculation of a pathlength-independent quality;
subtracting the substance contribution from the absorption data of the sample, thereby providing corrected absorption data of the analyte substantially free of a contribution from the substance;
using the corrected absorption data to calculate analyte concentration in the sample; and
providing the analyte concentration to a user.
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Abstract
A method determines an analyte concentration in a sample. The sample includes the analyte and a substance. The method includes providing absorption data of the sample. The method further includes providing reference absorption data of the substance. The method further includes calculating a substance contribution of the absorption data. The method further includes subtracting the substance contribution from the absorption data, thereby providing corrected absorption data substantially free of a contribution from the substance.
254 Citations
43 Claims
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1. A method of determining an analyte concentration in a sample, the sample comprising the analyte and a substance, the method comprising:
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providing absorption data of the sample; providing reference absorption data of the substance; calculating a substance contribution of the absorption data, wherein calculating the substance contribution comprises scaling the reference absorption data by multiplying the reference absorption data by a scaling factor, the scaling factor allowing for calculation of a pathlength-independent quality; subtracting the substance contribution from the absorption data of the sample, thereby providing corrected absorption data of the analyte substantially free of a contribution from the substance; using the corrected absorption data to calculate analyte concentration in the sample; and providing the analyte concentration to a user. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 16, 17, 18, 19, 20, 21, 22, 23)
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13. A method of determining an analyte concentration in a sample, the sample comprising the analyte and a substance, the method comprising:
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providing absorption data of the sample; providing reference absorption data of the substance; calculating a substance contribution of the absorption data, wherein calculating the substance contribution comprises scaling the reference absorption data by multiplying the reference absorption data by a scaling factor; subtracting the substance contribution from the absorption data of the sample, thereby providing corrected absorption data of the analyte substantially free of a contribution from the substance, wherein the reference absorption data is corrected for wavelength-dependent nonlinearities; and storing the corrected absorption data in a memory. - View Dependent Claims (14, 15)
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24. A method of providing measurements of constituents in a sample using infrared (IR) spectroscopy, the method comprising:
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providing absorption data of the sample, wherein providing absorption data comprises; placing the sample in a cuvette having a shape; passing IR radiation through a filter having a finite width; irradiating the cuvette with the IR radiation; and detecting a fraction of the IR radiation transmitted through the cuvette and the sample; correcting the absorption data for a non-analyte contribution to the absorption data, wherein the non-analyte contribution is from the finite width of the filter; and
providing the corrected absorption data to a user.
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25. A method of providing measurements of constituents in a sample using infrared (IR) spectroscopy, the method comprising:
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providing absorption data of the sample, wherein providing absorption data comprises; placing the sample in a cuvette having a shape; passing IR radiation through a filter having a finite width; irradiating the cuvette with the IR radiation; and detecting a fraction of the IR radiation transmitted through the cuvette and the sample; correcting the absorption data for a non-analyte contribution to the absorption data, wherein the non-analyte contribution is from the shape of the cuvette; and storing the corrected absorption data in a memory. - View Dependent Claims (26, 27)
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28. A method of using infrared (IR) spectroscopy to determine a ratio of an analyte volume to the total volume of a sample comprising the analyte, a first substance, and a second substance, the method comprising:
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providing absorption data from the sample for a first set of wavelengths in a wavelength region where a first-substance absorption dominates; calculating a first quantity equal to the product of a first-substance volume concentration and a path length of the sample; providing absorption data from the sample for a second set of wavelengths in a wavelength region where the first-substance absorption and a second-substance absorption dominate; calculating a second quantity equal to the product of a second-substance volume concentration and the path length of the sample; providing absorption data from the sample for a third set of wavelengths in a wavelength region where the first-substance absorption, the second-substance absorption, and an analyte absorption dominate; calculating a third quantity equal to the product of an analyte volume concentration and the path length of the sample; calculating a ratio of the third quantity divided by the sum of the first quantity, the second quantity, and the third quantity to achieve a pathlength-independent quantity; and storing the ratio in a memory. - View Dependent Claims (29, 30, 31, 32, 33)
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34. A method of determining non-analyte contributions to absorption data from a sample, the method comprising:
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(a) inputting transmission measurements, filter parameters, and water spectral properties; (b) calculating optical densities and filter constants; (c) estimating non-linear filter terms and cuvette distortion matrix elements; (d) solving for a temperature change as a function of the path length; and (e) calculating new estimates of absorption and non-linear terms. - View Dependent Claims (35, 36, 37)
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38. A method of determining non-analyte contributions to absorption data from a sample, the method comprising:
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(a) inputting transmission measurements, filter parameters, and water spectral properties; (b) calculating optical densities and filter constants; (c) estimating non-linear filter terms and cuvette distortion matrix elements; (d) solving for a temperature change as a function of the path length; and (e) calculating new estimates of absorption and non-linear terms. - View Dependent Claims (39)
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40. A method of evaluating analyte concentration errors in absorption data from a sample, the method comprising:
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calculating transmission and optical densities at four wavelengths for a water-filled cuvette, the four wavelengths comprising two wavelengths dominated by absorption by water, an analyte reference wavelength, and a measurement wavelength; using the optical densities to determine the water content at the analyte reference wavelength and the measurement wavelength; calculating expected optical density values at the analyte reference wavelength and the measurement wavelength; calculating residuals between the exact and calculated optical densities at the analyte reference wavelength and the measurement wavelength; determining the analyte concentration error by calculating the analyte concentration consistent with the difference between the residuals at the analyte reference wavelength and the measurement wavelength; and storing the analyte concentration error in a memory. - View Dependent Claims (41, 42, 43)
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Specification