Trace analysis of carbonyl compounds by liquid chromatography-mass spectrometry after collection as 2,4-dinitrophenylhydrazine derivatives

This study describes the utilization of carbonyl-2,4-dinitrophenylhydrazine (DNPH) derivatives for the determination of a micro amount of carbonyl compounds in air by liquid chromatography-mass spectrometry (LC-MS). After the carbonyl compounds are collected using a Waters Sep-Pak C-18 cartridge column with impregnated DNPH on octadecylsilica, they are eluted by acetonitrile as carbonyl-DNPH derivatives. A 20-mm(3) aliquot of eluent is injected into the LC-MS system. The four derivatives (formaldehyde-, acetaldehyde-, acrolein- and acetone-DNPH) were eluted within 7 min with acetonitrile-water (60:40, v/v) as the mobile phase. The proposed method offers sub-ppb sensitivity and good reproducibility and was applied to the determination of these carbonyl compounds in actual air samples from store rooms, laboratories and offices. The relative standard deviations for these samples (n=6) were 1 to 3%. (C) 1999 Elsevier Science B.V. All rights reserved.