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Carbonyl compounds play an important role in many environmental oxidation processes, but the identification of unknown carbonyl compounds can be difficult using existing techniques. We have developed an approach using derivatization with 0-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) followed by gas chromatography/mass spectrometry (GC/MS) analysis for the identification of unknown carbonyl compounds. Electron ionization, electron-capture negative chemical ionization, and positive chemical ionization mass spectrometry have all been examined using model compounds. Methods for identifying molecular weight are described, as well as methods for differentiating between different types of carbonyl compounds. GC/MS analysis of compounds containing carboxylic acid or hydroxyl groups in addition to the carbonyl group can be conducted by using PFBHA derivatization in conjugation with methylation and silylation. Electron ionization mass spectrometric analysis of the derivatives will usually provide for adequate molecular weight and structural information. The methods developed are demonstrated for three different types of samples.

Serine, a common aquatic amino acid, was treated with ozone and ozone decomposition products such as hydroxyl radicals. Scavengers and promoters were used to study ozone and hydroxyl radical reactions, respectively. Reactions of ozone and serine in the presence of hydroxyl radical scavengers led to the formation of carbonyl and carboxylic acid byproducts containing one or two carbon atoms, indicating the loss of a carbon from the original serine. Nitrite and nitrate were detected, with nitrate being the major end product from the oxidation of the amine nitrogen. Reaction of ozone with serine under radicalpromoting conditions led to the detection of compounds with one, two, and three carbon atoms, indicating that rupture of the original carbon backbone did not always occur. The byproducts detected included hydroxyl, carbonyl, and carboxylic acid functional groups. Under these conditions, ammonia was the major end product for the amine nitrogen.

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