Abstract
Authors have developed a new analytical method for gaseous carbonyl compounds in indoor air using a passive sampler. The sampler consists of a porous polyethylene cylinder uniformly packed with O-(4-cyano-2-ethoxybenzyl)hydroxylamine (CNET) coated silica gel as a reactive adsorbent. After sampling, CNET derivatives were eluted by acetonitrile and subsequently determined by HPLC. Sampling rates for formaldehyde, acetaldehyde and acetone were determined by a small chamber experiment with a constant gas generation system and resulted in 74 ml/min for formaldehyde, 44 ml/min for acetaldehyde and 42 ml/min for acetone. Effects of exposure time (8 and 24 hr), temperature (10, 25 and 40°C) and relative humidity (31-94%) on the rate were not apparent under the given conditions. The passive sampler was then applied for field measurements of carbonyl compounds in indoor air and gave similar results when compared to active samplings using 2,4-dinitrophenylhydrazine (DNPH) coated cartridges. The Ames test showed the CNET is preferable in safety handling because of its lower mutagenic activities than those of DNPH. Carbonyl compounds can be determined with reduced interference of ozone, because the CNET was less degradable when exposed to ozone compared with DNPH. Therefore, the CNET is a possible alternative to DNPH as trapping reagent in the passive sampling device for the determination of formaldehyde, acetaldehyde and acetone in indoor air.
