Determination of glyphosate and its metabolite aminomethylphosphonic 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.

Combination of supported liquid membrane and solid-phase extraction for sample pretreatment of triazine herbicides in juice prior to capillary electrophoresis determination.

A possibility of a combination of supported liquid membrane (SLM) and solid-phase extraction (SPE) for the determination of atrazine at microgram level in different type of fruit juices is presented. In comparison to SPE extraction from juice samples, the application of SLM-SPE enrichment provides much cleaner extracts and the possibility of lowering the limit of detection as low as 30 microg/l. However, it was also shown that by appropriate manipulation of SLM extraction conditions mainly flow-rate of donor phase and volume ratio between donor and acceptor phase, the level of detection can be further decreased to 10 microg/l. The results suggest that the application of SLM extraction prior to SPE is an alternative method for atrazine enrichment from complicated liquid matrices and could be used as routine method for the clean-up of such samples.