Abstract
A new solid sorbent passive air sampler used a coated Tenax TA pellet that chemisorbed aldehydes by reaction with 10% (w/w) O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride. The aldehyde permeated a silicone membrane to gain access to the sampling element at the end of a cylinder of diffusion path length 1.1 cm and diameter 1.3 cm. Vapors of known concentrations around the threshold limit values/time-weighted averages of n-valeraldehyde and acrolein and specific relative humidities (RH) were generated by syringe pumps in a dynamic generation and dilution system. An exposure chamber allowed measurement of face velocities, temperatures, exposing vapor concentrations, and RH. The O-oxime derivative was desorbed quantitatively with hexane, and an aliquot injected for gas chromatographic analysis on a low polarity capillary column using mass spectrometric or electron capture detection. The critical face velocity of the sampler was 15–20 ft/min and the capacity was about 30 µmoles. RH (3 ±1% to 79 ±2%) and temperature (4 ±1°C to 48 ±2°C) had no effects on the sampling constants of either aldehyde. Intermittent exposures had the same aldehyde equivalent recoveries as constant concentration exposures at the same time-weighted average. Stability after sampling was at least 6 months and the shelf life was over 3 months. The experimental sampling constants were 4.43 ±0.19 cm3/min for valeraldehyde and 7.73 ±0.57 cm3/min for acrolein.