Potential improvements aimed at high precision δC isotopic ratio determinations in CO mixtures using optical absorption spectrometry.

The manuscript explores some advantages and limitations of laser based optical spectroscopy, aimed at achieving robust, high-reproducibility CO and CO ratio determinations on the VPDB-CO δC scale by measuring the absorbance of line pairs of CO and CO. In particular, the sensitivities of spectroscopic lines to both pressure (P) and temperature (T) are discussed. Based on the considerations and estimations presented, a level of reproducibility of the CO/CO ratio determinations may be achieved of about 10.

Ultraviolet thermal lensing detection of amino acids.

Thermal lensing (TL) permits ultra-sensitive measurements of optical absorption of analytes in very small liquid volumes. We report the construction and use of a TL detector based on pulsed ultraviolet (UV) laser excitation (266 nm). We applied this detector to quantitate amino acids using capillary electrophoresis (CE) as a means of separation.