IDENTIFICATION OF CARBONYL-COMPOUNDS IN ENVIRONMENTAL-SAMPLES

Carbonyl compounds play an important role in many environmental oxidat ion processes, but the identification of unknown carbonyl compounds ca n be difficult using existing techniques. We have developed an approac h using derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylami ne hydrochloride (PFBHA) followed by gas chromatography/mass spectrome try (GC/MS) analysis for the identification of unknown carbonyl compou nds. Electron ionization, electron-capture negative chemical ionizatio n, and positive chemical ionization mass spectrometry have all been ex amined using model compounds. Methods for identifying molecular weight are described, as well as methods for differentiating between differe nt 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 met hylation and silylation. Electron ionization mass spectrometric analys is of the derivatives will usually provide for adequate molecular weig ht and structural information. The methods developed are demonstrated for three different types of samples.