Selective and Simultaneous Solid Phase Extraction of Polar and Non–Polar Organophosphorus Pesticides Using Sol–Gel Hybrid Silica–Based Sorbent

Abstract

A new sol–gel hybrid silica–based sorbent, methyltrimethoxysilane–cyanopropyltriethoxysilane (MTMOS–CNPrTEOS) produced in our laboratory was used for highly selective and simultaneous solid phase extraction (SPE) of two polar organophosphorus pesticides (OPPs) and four non–polar OPPs from water samples. The two polar OPPs used as test analytes are dicrotophos and methamidophos while the four non–polar OPPs are diazinon, malathion, methidathion, and chlorpyrifos. Analysis of OPPs was performed using gas chromatography–mass spectrometry in scan mode. Extraction efficiency (based on peak area response) of the new sol–gel hybrid MTMOS–CNPrTEOS was superior to commercial C18 SPE sorbent. The new sorbent showed higher selectivity towards the polar dicrotophos and methamidophos and it was also able to simultaneously extract the four non–polar OPPs with higher extraction efficiency. The limit of detection at S/N=3 for the new sol–gel hybrid sorbent is 5–9× lower and similar accuracy for the six OPPs compared to commercial C18 SPE sorbent. The new sol–gel hybrid material showed high potential as an alternative sorbent material for solid phase extraction of OPPs of wide polarity. It was successfully applied to the selective and simultaneous extraction the six OPPs from tap water and lake water samples.