Field sampling and determination of formaldehyde in indoor air with solid-phase microextraction and on-fiber derivatization

A new sampling and analysis method for formaldehyde in indoor air was tested in several indoor air surveys. The method was based on the use of solid-phase microextraction (SPME) poly(dimethylsiloxane)/divinylbenzene,65 mum fiber and gas chromatography. Indoor air surveys included grab and time-weighted average (TWA) sampling and were completed at six locations using (a) the SPME method employing on-fiber formaldehyde derivatization with o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride and (b)the conventional National Institute for Occupational Safety and Health (NIOSH) 2451 method. Sampling time for SPME fiber ranged from 10 min for grab sampling to 8 h for TWA sampling. Sampling locations included a residential house, a rental apartment, an office building, and industrial workplaces. The air concentrations measured by SPME ranged from 10 to 380 ppbv and correlated well with those estimated by the NIOSH method. Results also indicated th at in some cases the formaldehyde concentrations measured in residential air could be much higher than those allowed in occupational settings. The SPME method proved to be accurate, fast, sensitive, and cost-efficient in field sampling applications. This research should be of interest to research, industrial, and regulatory agencies as well as to the general public concerned with indoor air quality. Introduction