COMPARISON OF EXTRACTION METHODS AND DETECTION SYSTEMS IN THE GAS-CHROMATOGRAPHIC ANALYSIS OF VOLATILE CARBONYL-COMPOUNDS

High-resolution gas chromatography (HRGC) with electron-capture detect ion (ECD), nitrogen-phosphorus detection (NPD), flame ionization detec tion (FID) or with mass spectrometry-selected ion monitoring (MS-SIM) was used in the analysis of volatile carbonyl compounds. Eighteen carb onyl compounds that are typically produced during lipid peroxidation w ere derivatized quantitatively with pentafluorophenylhydrazine (PFPH) at room temperature, to afford their corresponding water-insoluble hyd razones. These derivatives were extracted into non-polar phases by mea ns of either liquid-liquid extraction (LLE) (hexane) or solid-phase ex traction (SPE) on 3 mi C-18 octadecyl-bonded phase cartridges. Detecti on limits of 10(-14) and 10(-12) mol/ml per aldehyde were achieved wit h the ECD and MS-SIM systems, respectively. The effects of extraction conditions on sensitivity and recovery were determined by performing p arallel HRGC-ECD and HRGC-MS-SIM analyses of pentafluorophenylhydrazon es of the eighteen compounds under study. Recoveries of 51.4-78.9+/-1. 2-4.5 and 80.9-98.3+/-1.0-3.5% were obtained with LLE and SPE, respect ively. The method was applied to the analysis of the volatile carbonyl compounds in various heated vegetable oils (corn, palm or sunflower) and to the analysis of volatile aldehydes in human urine. (C) 1997 Els evier Science B.V.