A simple and effective method for the detection of three pesticides (chlorpyrifos, diazinon and cyprodinil) is developed using a polymer inclusion membrane (PIM) prior to gas chromatography and mass spectrometry detection (GC-MS). Analytes are extracted from natural water samples using a 3 cm2 PIM made of the polymer, cellulose triacetate (CTA), and the plasticizer, nitrophenyl octyl ether (NPOE). Addition of the plasticizer to the CTA matrix is found to be necessary for the extraction of pesticides. After extraction, analytes are recovered from the membrane with 1 mL of acetonitrile and injected into the GC-MS system. The main factors affecting the extraction efficiency are evaluated, including membrane composition, stirring mode, extraction and elution time. Ultrasonic assisted elution of the extracted pesticides is accomplished after 15 min of contact. The PIM-assisted extraction method makes it possible for pesticides to be determined in the range of 50-1000 ng L-1 with good linearity (coefficient of determination ≥0.995) and suitable recoveries (85-119%) and precision (<21%, n = 3) using 100 mL of a water sample. This methodology is shown to be suitable for the detection of chlorpyrifos in local river waters.
Keywords: Extraction phase; Pesticides; Polymer inclusion membrane; River water.
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