Abstract: A method of fuel analysis comprising subjecting a fuel sample comprising a fuel marker and a fuel matrix to fluorescence spectroscopy to generate a measured emission spectrum comprising a first spectral component (type and amount of marker in sample), a second spectral component (spectral perturbation), and a third spectral component (matrix fluorescence); deconvoluting the measured emission spectrum to yield a deconvoluted measured emission spectrum (first and second spectral components) via removal of third spectral component; decoupling the deconvoluted measured emission spectrum to yield a corrected emission spectrum (first spectral component) via a projection function which orthogonally projects the deconvoluted measured emission spectrum onto a subspace devoid of the second spectral component; and determining the amount of fuel marker in the fuel sample from the corrected emission spectrum. The method of fuel analysis comprises temperature corrections.

Abstract: A method of fuel analysis comprising subjecting a fuel sample comprising a fuel marker and a fuel matrix to fluorescence spectroscopy to generate a measured emission spectrum comprising a first spectral component (type and amount of marker in sample), a second spectral component (spectral perturbation), and a third spectral component (matrix fluorescence); deconvoluting the measured emission spectrum to yield a deconvoluted measured emission spectrum (first and second spectral components) via removal of third spectral component; decoupling the deconvoluted measured emission spectrum to yield a corrected emission spectrum (first spectral component) via a projection function which orthogonally projects the deconvoluted measured emission spectrum onto a subspace devoid of the second spectral component; and determining the amount of fuel marker in the fuel sample from the corrected emission spectrum. The method of fuel analysis comprises temperature corrections.

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.

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.

Abstract: Methods and systems for calculating tissue oxygenation, e.g., oxygen saturation, in a target tissue are disclosed. In some embodiments, the methods include: (a) directing incident radiation to a target tissue and determining reflectance spectra of the target tissue by measuring intensities of reflected radiation from the target tissue at a plurality of radiation wavelengths; (b) correcting the measured intensities of the reflectance spectra to reduce contributions thereto from skin and fat layers through which the incident radiation propagates; (c) determining oxygen saturation in the target tissue based on the corrected reflectance spectra; and (d) outputting the determined value of oxygen saturation.

Abstract: The invention relates to systems and methods for measuring properties of samples with standardized spectroscopic systems. The methods can include (i) measuring, with a first spectroscopic system, spectra of at least three different reference targets; (ii) calibrating the first spectroscopic system; (iii) measuring, with the first spectroscopic system, a spectrum of a known reference specimen having a known value of the property; (iv) generating a model for the measured property using the spectrum of the known reference specimen; (v) measuring, with a second spectroscopic system, the spectra of at least three different reference targets; (vi) calibrating the second spectroscopic system; (vii) applying the model to the second spectroscopic system; (viii) measuring a spectrum of the sample using the second spectroscopic system; and (ix) determining a value of the property using the model.

Abstract: We disclose measurement systems and methods for measuring analytes in target regions of samples that also include features overlying the target regions. The systems include: (a) a light source; (b) a detection system; (c) a set of at least first, second, and third light ports which transmit light from the light source to a sample and receive and direct light reflected from the sample to the detection system, generating a first set of data including information corresponding to both an internal target within the sample and features overlying the internal target, and a second set of data including information corresponding to features overlying the internal target; and (d) a processor configured to remove information characteristic of the overlying features from the first set of data using the first and second sets of data to produce corrected information representing the internal target.