Workplace monitoring of oximes using 2,4-dinitrophenylhydrazine-coated silica gel cartridges and liquid chromatography

A liquid chromatographic (LC) method for the determination of oximes in air samples using pre-column derivatization with a hydrazine reagent has been developed. Air samples are drawn over a 2,4-dinitrophenylhydrazine (DNPH)-c oated silica gel cartridge to form the corresponding hydrazones. The acid c oating of the tubes and the flow rate of the air sample have been selected considering the chemical characteristics of the oximes to avoid Beckmann re arrangement or incomplete recovery. The hydrazones are separated by LC with UV/Vis detection at 365 nm. Calibration is performed externally using the stable hydrazone standards, The limit of quantification is 0.5 pmol absolut e for 2-butanone oxime (corresponding to 15.0 ng/l in a 21 air sample) and cyclohexanone oxime (corresponding to 19.5 ng/l in a 21 air sample), respec tively. Real samples from industrial workplaces have successfully been anal ysed using this method, (C) 1999 Elsevier Science B.V. All rights reserved.