Multiresidue determination of pesticides from aquatic media using polyaniline nanowires network as highly efficient sorbent for microextraction in packed syringe.

A simple, rapid and sensitive method based on microextraction in packed syringe (MEPS), in combination with gas chromatography-mass spectrometry (GC-MS) was developed. Polyaniline (PANI) nanowires network was synthesized and used as sorbent of MEPS for the multiresidue determination of selected analytes from triazine, organochlrorine and organophosphorous pesticides in aqueous samples. The PANI nanowires network was prepared using soft template technique and its characterization was studied by scanning electron microscopy (SEM). The presence of micelles in this methodology showed to be an important parameter in shaping the growing polymer. Hexadecyltrimethylammonium bromide (HTAB) was used as structure directing agent in PANI preparation procedure and this was led to the formation of nanowires with diameters ranging from 35 nm to 45 nm. The synthesized PANI nanowires network showed higher extraction capability in comparison with the bulk PANI. Important parameters influencing the extraction and desorption processes including desorption solvent, elution volume, draw-eject cycles of sample, draw-eject mode, pH effect and amount of sorbent were optimized. Limits of detection were in the range of 0.07-0.3 ng mL(-1) using time scheduled selected ion monitoring (SIM) mode. The linearity of method was in the range from 0.5-200 ng mL(-1) to 0.2-1000 ng mL(-1). The method precision (RSD %) with three replicates were in the range of 5.3-18.4% at the concentration level of 5 ng mL(-1). The developed method was successfully applied to the Zayandeh-rood river water samples and the matrix factor obtained for the spiked real water samples were in the range of 0.79-0.94.