COLLECTION AND ANALYSIS OF TRACE FORMIC AND ACETIC-ACID VAPORS IN AIR USING AMINOPROPYL-MODIFIED SURFACES

Quartz filter surfaces were modified with aminopropyltrialkoxysilanes and used to collect gas phase acids. The filters were chemically characterized by titrimetric, gravimetric, and chromatographic methods; on the basis of these experiments, filter preparation methods were optimized. Analytical procedures for formic and acetic acids were developed based on their displacement from a sampled surface by a strong acid eluant and subsequent analysis of the eluant by ion chromatography. Passive collection of the acids from air and elution of the acids from the filter were highly efficient; in active sampling, efficiency of collection for acetic acid was less consistent than for formic acid. Analytical results from samples taken in Las Vegas are reported; concentration levels are consistent with previously reported values. © 1994 Academic Press. All rights reserved.