Reinforced polydiphenylamine nanocomposite for microextraction in packed syringe of various pesticides

► A method based on microextraction in packed syringe coupled off-line with GC–MS was developed. ► Polydiphenylamine reinforced with carbon nanotube (PDPA/CNT) was synthesized in the presence of cetyltrimethylammonium bromide. ► The PDPA/CNT nanocomposite was used as sorbent for the extraction of multiclass pesticides from aquatic media. Reinforced polydiphenylamine (PDPA) nanocomposite was synthesized by oxidation of diphenylamine in 4 mol L −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 200 μL of n-hexane. Limits of detection (LODs) were in the range of 0.01–0.1 ng mL −1 and 0.02–0.1 ng mL −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 5 ng mL −1 while the linearity of method was in the range of 0.15–100 and 0.5–500 ng mL −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.