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Reinforced polydiphenylamine nanocomposite for microextraction in packed syringe of various pesticides

Habib Bagheri, Zahra Ayazi, Ali Es’haghi, Ali Aghakhani
Journal of chromatography 2012 v.1222 no. pp. 13-21
aquatic environment, carbon nanotubes, cetyltrimethylammonium bromide, desorption, detection limit, diphenylamine, gas chromatography-mass spectrometry, hexane, microextraction, monitoring, nanocomposites, oxidation, pesticide residues, propionic acid, river water, scanning electron microscopy, sulfuric acid, surfactants, triazines, water pollution
Reinforced polydiphenylamine (PDPA) nanocomposite was synthesized by oxidation of diphenylamine in 4molL⁻¹ sulfuric acid solution containing a fixed amount of carbon nanotubes (CNTs) in the presence of cetyltrimethylammonium bromide (CTAB). The surface characteristic of PDPA and PDPA/CNT nanocomposites was investigated using scanning electron microscopy (SEM). The prepared PDPA/CNT nanocomposite was used as an extraction medium for microextraction in packed syringe (MEPS) of selected pesticides from aquatic environment. The effect of CNT doping level and the presence of surfactant on the extraction capability of nanocomposite was investigated and it was revealed that when 4% (w/w) of CNT in the presence of CTAB is being used, the highest extraction recovery could be achieved. Eventually, the developed MEPS technique in off-line combination with gas chromatography–mass spectrometry (GC–MS) was applied to the analysis of some pesticides including triazine, organophosphorous, organochlorine and aryloxyphenoxy propionic acid pesticides. Important parameters influencing the extraction and desorption processes were optimized and a 25 cycles of draw-eject gave maximum peak area, when desorption was performed using 200μL of n-hexane. Limits of detection (LODs) were in the range of 0.01–0.1ngmL⁻¹ and 0.02–0.1ngmL⁻¹ for distilled water and river water respectively, using time scheduled selected ion monitoring (SIM) mode. The method precision (RSD %) with four replicates was in the range of 1.6–14.6% for distilled water and 1.5–16.2% for river water at the concentration level of 5ngmL⁻¹ while the linearity of method was in the range of 0.15–100 and 0.5–500ngmL⁻¹. The developed method was successfully applied to different river water samples and the matrix factor for the spiked river water samples were found to be in the range of 0.74–1.09.