Comparison of stir bar sorptive extraction and membrane-assisted solvent extraction as enrichment techniques for the determination of pesticide and benzo[a]pyrene residues in Brazilian sugarcane juice

The present work compares two modem and environmentally friendly enrichment techniques, stir bar sorptive extraction (SBSE) and membrane-assisted solvent extraction (MASE) for the determination of 18 organic contaminant residues in Brazilian sugarcane juice. Stir bar sorptive extraction and thermal desorption coupled to capillary gas chromatography-mass spectrometry using the selected ion monitoring mode [SBSE-TD-GC-MS(SIM)] and membrane-assisted solvent extraction combined with large volume injection [MASE-LVI-GC-MS (SIM)] methods were assessed taking into account the time of extraction [SBSE (3 h) and MASE (30 min)], the recoveries [SBSE (0.2-55.3%) and MASE (13.6-103.1%)], the repeatability [SBSE (0.3-19.2%) and MASE (2.6-18.4%)] and the limits of detection [SBSE (0.002-0.71 mu g L-1) and MASE (0.004-0.56 mu g L-1)] of the selected triazine, organochlorine and organophosphorus pesticides as well as benzo[a]pyrene in sugarcane juice. In general, faster analyses and much better analyte recovery results were achieved with MASE, whereas greater sensitivity and repeatability were obtained with SBSE. SBSE and MASE procedures were applied to the analysis of six sugarcane juice samples from the city S (a) over tildeo Carlos, in the state of S (a) over tildeo Paulo, Brazil. A comparison of the results of the pesticide and benzo[a]pyrene residues at mu g L-1 level obtained by the two methods showed good agreement. (c) 2006 Elsevier B.V. All rights reserved.