On-line Derivatisation in Combined High-performance Liquid Chromatography–Gas Chromatography–Mass Spectrometry

Abstract

Procedures are reported for the combined HPLC–GC and HPLC–GC–MS analysis of involatile analytes using on-line derivatisation. Derivatisation was carried out between the HPLC and the GC separation stages using two approaches; pre-mixing of the derivatisation reagent and the analytes in the HPLC effluent ahead of the GC pre-column, and independent reagent delivery after deposition of the desolvated analytes in the GC pre-column. The derivatisation of the stilbene hormones, quinoxaline-2-carboxylic acid, sulfamethazine and 2-naphthoic acid with silylation, methylation and acetylation reagents was investigated. Derivatisation efficiencies in the range 84–100% were achieved for the stilbene hormones and acidic compounds. The HPLC–derivatisation–GC procedure was demonstrated for the determination of the stilbene hormones in processed meats with detection limits between 0.17 and 0.47 µg kg ^{- 1} and RSDs in the range 2.3–4.9% for HPLC–GC with electron ionization quadrupole ion trap MS detection.