Keggin-type polyoxometalate embedded polyvinylidene fluoride for thin film microextraction of organophosphorus pesticides.

The present research is the first report on the application of Keggin-type phosphotungstic acid/polyvinylidene fluoride membrane. This compound as a simple, cost-effective and novel sorbent was used for the extraction and pre-concentration of two organophosphorus pesticides in real samples in the thin film solid-phase microextraction (TFME) method. TFME as one of the sub-branches of solid phase microextraction resolves the problems of SPME methods, including their limited absorption capacity. These extraction methods have a high surface-to-volume ratio, which improves their sensitivity compared to other geometries. Under optimal conditions, the limit of detections (LODs), the limit of quantifications (LOQs), and relative standard deviation (RSD) of this method varied in the ranges of 0.29-0.31 μg L, 0.96-1.0 μg L, and 3.9%-6.2%, respectively. This method showed a linear dynamic range (LDR) of 1.0-500 μg L with a coefficient of determination (r) above 0.9978. This promising method was used to analyze malathion and diazinon.