Subnanomolar Sensitive Stable Isotopic Determination in CO by Tunable Infrared Laser Absorption Spectroscopy.

Oxygen and carbon stable isotope ratios (O/O, C/C, and O/O) of CO have been crucial in helping us understand Earth and planetary systems. These ratios have also been used in medicine for the noninvasive diagnosis of diseases from exhaled breath and for quantifying biochemical or metabolic reactions and in determining the production area of agricultural products. The current method for measuring the stable isotope ratios of CO is primarily gas-source isotope ratio mass spectroscopy (IRMS).