CAN AN IR DIODE-LASER SPECTROMETER BE USED FOR THE DETERMINATION OF NATURAL ISOTOPE RATIOS IN BIOLOGICAL SAMPLES

An IR diode laser spectrometer can detect the enrichment of stable iso topes (C-13 [1] and N-15[2]) in tracer studies. However our system can not detect differences of the natural abundances of these isotopes. Th is problem is not a principal limitation of the IR diode laser spectro scopy, but is inherent to our standard system. A new isotope ratio IR diode laser spectrometer has an accuracy high enough for most biologic al applications. Some advantages like flexibility in measuring differe nt isotopes, insensitivity against other gases in the sample and price are correlated to this system.