Determining the quantity of a taggant in a liquid sample
First Claim
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1. A liquid sample analysis method comprising;
- providing an excitation light and a broadband light to a liquid sample;
obtaining, by a fluorescence spectrometer, measured emission pre-spectrum from the liquid sample;
storing the measured emission pre-spectrum in a memory;
determining a peak of the measured emission pre-spectrum, wherein the peak comprises a first intensity;
adjusting, when the first intensity is outside a desired range, an integration time to produce a measured emission spectrum of intensity versus wavelength;
generating a predicted concentration of a fluorescent tagging compound in the liquid sample using the measured emission spectrum;
comparing the predicted concentration of the fluorescent tagging compound in the liquid sample to a preset concentration of the fluorescent tagging compound in the liquid sample; and
determining whether the measured emission spectrum is a member of a class for a sub-model based on spectral fitness metrics,wherein the spectral fitness metrics comprise a spectrum fit based on the measured emission spectrum, a matrix of spectrum weights, and a matrix of spectrum loadings.
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Abstract
Device and methods for detecting/quantifying a fluorescent taggant in a liquid sample. Generally, the liquid samples are fuels having low concentrations (measured in ppb) of a fluorescent taggant. The detection/quantification generates a predicted concentration of the fluorescent tagging compound using a process selected from the group of a multivariate process, a background subtraction process, or a combination of both. The invention addresses the detection of an adulteration of gasoline and diesel fuels.
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Citations
22 Claims
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1. A liquid sample analysis method comprising;
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providing an excitation light and a broadband light to a liquid sample; obtaining, by a fluorescence spectrometer, measured emission pre-spectrum from the liquid sample; storing the measured emission pre-spectrum in a memory; determining a peak of the measured emission pre-spectrum, wherein the peak comprises a first intensity; adjusting, when the first intensity is outside a desired range, an integration time to produce a measured emission spectrum of intensity versus wavelength; generating a predicted concentration of a fluorescent tagging compound in the liquid sample using the measured emission spectrum; comparing the predicted concentration of the fluorescent tagging compound in the liquid sample to a preset concentration of the fluorescent tagging compound in the liquid sample; and determining whether the measured emission spectrum is a member of a class for a sub-model based on spectral fitness metrics, wherein the spectral fitness metrics comprise a spectrum fit based on the measured emission spectrum, a matrix of spectrum weights, and a matrix of spectrum loadings. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A liquid sample emission spectrum classification method comprising:
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obtaining, by a fluorescence spectrometer, a liquid sample emission pre-spectrum for a liquid sample; storing the liquid sample emission pre-spectrum in a memory; determining a peak of the liquid sample emission pre-spectrum, wherein the peak comprises an intensity; adjusting, when the intensity is outside a desired range, an integration time to produce a liquid sample emission spectrum of intensity versus wavelength; determining whether the liquid sample emission spectrum is a member of a class for a sub-model based on spectral similarity metrics; determining whether the liquid sample emission spectrum is the member of the class for the sub-model based on spectral fitness metrics, wherein the spectral fitness metrics comprise a spectrum fit based on the liquid sample emission spectrum, a matrix of spectrum weights, and a matrix of spectrum loadings; and classifying the liquid sample emission spectrum as in-model. when the liquid sample emission spectrum is a member of the class for the sub-model based on the spectral similarity metrics and the spectral fitness metrics. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A liquid sample analysis method comprising:
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obtaining, by a fluorescence spectrometer, a measured emission pre-spectrum for a liquid sample; storing the measured emission pre-spectrum in a memory; determining a peak of the measured emission pre-spectrum, wherein the peak comprises an intensity; adjusting, when the intensity is outside a desired range, an integration time to produce a measured emission spectrum of intensity versus wavelength; selecting a sub-model for the measured emission spectrum; determining whether the measured emission spectrum is a member of a class for the sub-model based on spectral fitness metrics, wherein the spectral fitness metrics comprise a spectrum fit based on the measured emission spectrum, a matrix of spectrum weights, and a matrix of spectrum loadings determining whether the measured emission spectrum is in-model for the sub-model; determining whether the sub-model is associated with an inclusive flag; and performing a quantitative analysis on the measured emission spectrum when the measured emission spectrum is in-model for the sub-model and the sub-model is associated with the inclusive flag. - View Dependent Claims (20, 21, 22)
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Specification