IDENTIFICATION OF CARBONYL-COMPOUNDS IN ENVIRONMENTAL-SAMPLES

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 O-(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.