Passive sampling and head space analysis for quantitative determination ofnitrous oxide exposure

A new technique has been developed for determining the time-weighted averag e personal exposure to nitrous oxide gas. Nitrous oxide gas is passively co llected on a molecular sieve contained in a glass tube and partially desorb ed in a vial until solid-gas equilibrium at 100 degrees C. Next, nitrous ox ide concentration in the head space air in the vial is measured with a gas chromatograph equipped with an electron capture detector. This study shows that nitrous oxide concentration in the head space air is proportional to b oth the nitrous oxide concentration in the test atmosphere and the sampling time up to 1600 ppm/hr. The coefficient of variance is less than 10%, The performance of the sampler is not affected by water vapor or carbon dioxide in the atmosphere nor by air currents. The sampler can be stored for 2 wee ks at either 4 or 25 degrees C. Because the passive sampler is small and li ght, it can be used to determine exposure to nitrous oxide during surgical operations.