A Polypyrrole-Based Sorptive Microextraction Coating for Preconcentration of Malathion from Aquatic Media

Abstract

A new micro-solid phase extraction method was developed by combining solid-phase extraction and stir bar sorptive extraction to benefit from the advantages of both techniques. A polypyrrole coating was electrochemically synthesized on the surface of an already used graphite furnace, employed in electro-thermal atomic absorption spectroscopy. The cylindrical geometry of the graphite tube provided a rather huge surface area, suitable for sorptive extraction. The novel sorbent coating was examined as an extracting medium to isolate malathion. Effects of different parameters such as extraction time, salt concentration, sample volume, desorption solvent and time were investigated and optimized. Under the optimized conditions, the limit of detection and limit of quantification of the developed method were 5 and 20 ng L -1 , respectively. The calibration curve showed linearity in the range of 0.1-100 lg L -1 (R 2 = 0.9968). The precision was evaluated at 0.1 and 1 lg L -1 concentration levels and relative standard deviations (n = 3) were found to be 10 and 7%, respectively. The developed method was successfully applied to the extraction of malathion from real river water and tap water samples, and relative recoveries at the spiked level of 0.1 lg L -1 were 94 and 97%, respectively.