Patent ID: 8750952

Claim:
A method of dating a body sample comprising: taking a spectroscopic measurement of a host material; taking a series of spectroscopic measurements of the sample, each measurement in the series of spectroscopic measurements including at least two predetermined positions in a spectrum, the predetermined positions having spectral characteristics corresponding to two predetermined substances present in the sample that have a time varying relationship with each other, the measurements in the series of spectroscopic measurements being spaced in time; determining a concentration of each of the two predetermined substances present in the sample from each measurement in the series of the spectroscopic measurements at each point in time; determining a ratio of the concentrations of the two predetermined substances at each point in time; analyzing the ratios of the concentrations of the two predetermined substances over time to estimate when the concentrations of the two predetermined substances were at a limit of their concentrations, thereby providing an indication of the age of the sample; and wherein determining the concentrations of the two predetermined substances from the series of spectroscopic measurements comprises: dividing a measured absorbance spectrum obtained from the series of spectroscopic measurements of the sample by an assumed optical path length to provide a corrected absorbance spectrum; fitting measured spectra of the two predetermined substances to the corrected absorbance spectrum to obtain a residue, and fitting the spectroscopic measurement of the host material to the residue to obtain relative concentrations of the two predetermined substances within the sample.