A recommendation for combining the standard analytical methods for the determinations of formaldehyde and total aldehydes in air

Abstract

For determining formaldehyde, the Intersociety Committee of the American Public Health Association recommends a method using chromotropic acid (CA), and for determining total aliphatic aldehydes a method using 3-methyl-2-benzothiazolone hydrazone (MBTH). In field studies, the use of these separate methods involves performing many tasks in parallel and in duplicate. Inspection of the chemistry underlying the MBTH method suggested that the CA method might be successfully applied to MBTH-containing samples, provided that MBTH did not act as an interferent. We applied the recommended CA method to water and 0.05% MBTH impinger solutions from parallel sampling trains at six field sites, and found the mean formaldehyde levels to differ on the average by 5%. Having established that a single MBTH sample can yield both the formaldehyde and total aliphatic aldehyde contents of a sampled atmosphere we devised a combined method with improved techniques that streamlined laboratory analysis by maximizing procedural overlap.