Determination of glyphosate and its metabolite aminomethylphosponic acid in fruit juices using supported-liquid membrane preconcentration method with high-performance liquid chromatography and UV detection after derivatization with p-toluenesulphonyl chloride

The application of supported-liquid membrane (SLM) technique for effective extraction of N-(phosphonomethyl)glycine (glyphosate) and its primary metabolite aminomethylphosphonic acid (AMPA) from juices (orange, grapefruit, apple and blackcurrant) in combination with HPLC-UV detection after derivatization with p-toluenesulphonyl chloride (TsCl) is presented. The influence of various parameters such as the composition of acceptor phase, flow-rate, concentration of analytes, on the performance of extraction procedure, was studied. It was shown that by appropriate manipulation of SLM parameters the level of detection could be significantly improved. The influence of SLM conditions on extraction efficiency of studied compounds was also discussed. Selection of the optimal conditions enable detection of glyphosate and AMPA in juices at concentrations as low as 0.025 mg/l. The calculated recoveries for glyphosate were-71.1, 72.1, 93.6, and 102.7% and for AMPA-64.1, 64.6, 81.7, and 89.2%, for orange, grapefruit, apple and blackcurrant juices, respectively. The results suggest that the application of SLM extraction as a method for glyphosate and AMPA enrichment from complicated liquid matrices may be useful mean of routine analysis. (c) 2005 Elsevier B.V. All rights reserved.