Patent ID: 7336989

Claim:
A system for determining the presence and/or concentration of an exogenous substance in a material, said system comprising: a) an energy-emitting device which projects a flow of energy onto or into the material, said energy being effective to i) ablate at least some of the material and ii) cause the exogenous substance, if present within the ablated material, to emit fluorescence; b) a spectrum generating device which generates fluorescence spectra on the basis of the fluorescence emitted by the exogenous substance; and c) a spectral processing device, which uses the fluorescence spectra to determine the presence or concentration of the substance, said spectral processing device comprising; i) means for collecting and saving data from the spectrograph, ii) means for identifying first and second spectral peaks corresponding to first and second wavelengths on the spectrum, iii) means for calculating a ratio between the fluorescence at the second spectral peak and the fluorescence at the first spectral peak and for determining the concentration based on the ratio and iv) output means for displaying the concentration.