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 mg kg 21 and RSDs in the range 2.3-4.9% for HPLC-GC with electron ionization quadrupole ion trap MS detection.

Determination of natural and synthetic estrogens in water by gas chromatography with mass spectrometric detection

“…Silylation of all hydroxyl groups contained in the considered analytes was achieved using MSTFA, without the addition of any catalyser, probably because of its smaller size, it can approach effectively to the hindered -OH hydroxyl groups of mestranol and ethinylestradiol which did not react with BSTFA. Independently of the employed derivatization reagent (MTBSTFA, BSTFA or MSTFA), two peaks, with the same mass spectra, were always obtained for diethylstilbestrol; it was assumed that they corresponded to the cis and trans isomers [19].…”

Derivatization in Mass Spectrometry– 3. Alkylation (Arylation)

“…37 Two approaches for derivatization were investigated. The first one involves pre-mixing of the reagent with the HPLC effluent prior to introduction into the GC column.…”

Solid-phase extraction or liquid chromatography coupled on-line with gas chromatography in the analysis of biological samples

“…On-line derivatisation in the GC precolumn has been accomplished with both the loop-type interface and the on-column interface. In the latter case, silylation, acylation and methylation reactions have been demonstrated for NPLC-GC [16]. The procedure was either to premix the reagent and the analytes in the HPLC effluent before the GC precolumn, or to deliver the reagent independently after the transfer and the evaporation process.…”

“…NPLC-GC has also been used in the analysis of stilbene hormones in meat extracts [16]. The NPLC-GC method that was developed involved an on-line derivatisation step.…”

“…Yet, further advantages are the shortened time of analysis and better reliability and repeatability. For biological and pharmaceutical samples, both SPE and LC have been coupled on-line with GC [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Also other on-line techniques, such as membrane extraction and on-line LLE, have been directly coupled with GC, but these methods are not covered in this review.…”