Method and apparatus for comparing spectra
First Claim
1. A method for determining concentration of a selected analyte in a sample, the analyte having a characteristic spectral band in a selected spectral region within a range consisting of infrared, visible and ultraviolet radiation, the method comprising:
- generating an analyte spectrum of a selected analyte including the spectral band;
generating a sample spectrum of a sample for the selected spectral region;
computing a first derivative of the sample spectrum;
constructing a matrix model comprising as components the analyte spectrum and the first derivative of the sample spectrum; and
applying the matrix model to the sample spectrum so as to yield a parameter representing concentration of the selected analyte in the sample.
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Abstract
A method for determining concentration of an analyte in a sample includes generating a spectrum of a selected analyte and interferents, generating a spectrum of an unknown sample, computing first and second derivatives of the sample spectrum, deriving a matrix model that includes the analyte spectrum and the derivatives, and applying the matrix model to the sample spectrum so as to yield a parameter representing concentration of the selected analyte in the unknown sample. Multiple linear least squares regression is utilized to fit the model and calculate the parameter.
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Citations
22 Claims
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1. A method for determining concentration of a selected analyte in a sample, the analyte having a characteristic spectral band in a selected spectral region within a range consisting of infrared, visible and ultraviolet radiation, the method comprising:
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generating an analyte spectrum of a selected analyte including the spectral band; generating a sample spectrum of a sample for the selected spectral region; computing a first derivative of the sample spectrum; constructing a matrix model comprising as components the analyte spectrum and the first derivative of the sample spectrum; and applying the matrix model to the sample spectrum so as to yield a parameter representing concentration of the selected analyte in the sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for determining concentration of a selected analyte in a sample, the analyte having a characteristic spectral band in a selected spectral region within a range consisting of infrared, visible and ultraviolet radiation, the method comprising:
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generating and storing an analyte spectrum of a selected analyte including the spectral band; generating a sample spectrum of a sample for the spectral region; for each incremental wavelength position, selecting a plurality of points in the sample spectrum centered on such wavelength position, fitting a curve to the plurality of points, and computing a first derivative and a second derivative of the sample spectrum from the fitted curve; constructing a matrix model comprising as components the analyte spectrum, the first derivative of the sample spectrum and the second derivative of the sample spectrum; utilizing a multiple linear least squares regression method to apply the matrix model to the sample spectrum so as to yield a parameter representative of concentration of the selected analyte in the sample; and generating at least one further sample spectrum, deriving a further matrix model with the stored spectrum and first and second derivatives of the further spectrum, and utilizing the regression method with the further matrix model to yield a further value of the parameter representative of concentration of the selected analyte in the sample.
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14. An apparatus for determining concentration of a selected analyte in a sample, the analyte having a characteristic spectral band in a selected spectral region within a range consisting of infrared, visible and ultraviolet radiation, the apparatus comprising:
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means for generating an analyte spectrum of a selected analyte including the spectral band; means for generating a sample spectrum of a sample for the spectral region; means for computing a first derivative of the sample spectrum; means for constructing a matrix model comprising as components the analyte spectrum and the first derivative of the sample spectrum; and means for applying the matrix model to the sample spectrum so as to yield a parameter representing concentration of the selected analyte in the sample. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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Specification