AUTOMATED-ANALYSIS OF GASES STORED IN VACUTAINER VIALS

Trace gas research is often constrained by the number of samples to be analyzed. We report here, modifications to a commercially available h eadspace gas autosampler for sampling stored gas in blood collection v ials (Vacutainer Brand). The sampler was modified to: a) accommodate a 0.5-mL gastight syringe, b) accept 3-mL Vacutainer vials, and c) ensu re the syringe needle dislodged from the vial septum. Sample volumes u sing the modified sampler were consistent from vial to vial. For the d etermination of the nitrous oxide (N2O) concentration of a known refer ence, we found a coefficient of variation of 3% with the modified auto sampler compared to 1% with manual injections. The modification of two autosamplers has permitted analysis of 90 sample vials per day for N2 O, carbon dioxide (CO2), oxygen (O2), acetylene (C2H2), and nitrogen ( N2) gases using one gas chromatograph with two detector systems. As a consequence, we have increased sample numbers, reduced associated labo ur costs and maintained analysis quality.