COLLECTION OF FORMALDEHYDE FROM CLEAN-AIR FOR CARBON ISOTOPIC ANALYSIS

A method has been developed for collecting milligram quantities of formaldehyde from clean air (sub-ppb levels) onto dry, sulfito-treated glass substrates. Spectrometric and chromatographic characterizations of the surface were performed to establish conditions for optimal collection. Efficiency of collection for formaldehyde is dependent on the fractional oxidation of the filter surface, as well as on ambient humidity; the rate of oxidation is cation dependent. Under favorable conditions, collection efficiencies of over 90% (based on breakthrough in a multiple-filter stack) are routinely obtained. Selectivity of collection is high, and the possibility of artifact formation is minimal. Preliminary 13C data for two remote sampling sites have been obtained. © 1990, American Chemical Society. All rights reserved.