Patent ID: 6794649
Filing Date: 2004-09-21
Classification: G01N

Abstract:
A method for determining the monotonic functional relationship between (A) the integrated absorbance of spectral energy within a spectral region of interest of an analyte that decomposes during the time experimental spectral data for determining the relationship are being obtained and whose spectral data are pressure sensitive below a total pressure P and (B) the concentration of the analyte before decomposition commences, the method comprising the steps:(a) for a first known initial concentration of the analyte and while intentionally maintaining the total pressure at a pressure not less than pressure P because of the spectral data being pressure sensitive below pressure P: (i) determining the integrated absorbance of spectral energy within the spectral region of interest at a first time after the commencement of the obtention of spectral data, (ii) determining the integrated absorbance of spectral energy within the spectral region of interest at one or more times subsequent to the first time and different from each other if more than one subsequent time is used, and (iii) extrapolating from the integrated absorbance for the first time and the one or more subsequent times to the time at which the decomposition of the analyte commences to thereby establish at a time before the decomposition commences an estimated integrated absorbance of spectral energy within the spectral region of interest for the first known initial concentration; (b) for each of one or more additional known initial concentrations of the analyte different from the first known concentration and different from each other if more than one additional initial concentration is used and while intentionally maintaining the total pressure at a pressure not less than pressure P because of the spectral data being pressure sensitive below pressure P: (i) determining the integrated absorbance of spectral energy within the spectral region of interest at a first time after the commencement of the obtention of spectral data, (ii) determining the integrated absorbance of spectral energy within the spectral region of interest at one or more times subsequent to the first time and different from each other if more than one subsequent time is used, and (iii) extrapolating from the integrated absorbance for the first time and the one or more subsequent times to the time at which the decomposition of the analyte commences to thereby establish at a time before the decomposition commences an estimated integrated absorbance of spectral energy within the spectral region of interest for each of the one or more additional known initial concentrations; and (c) associating each of the known initial concentrations with its respective estimated integrated absorbance of spectral energy within the spectral region of interest to thereby determine for the analyte at a total pressure not less than pressure P the monotonic functional relationship between the concentration before the decomposition commences and the integrated absorbance of spectral energy within the spectral region of interest of the analyte.