The Dispersive Liquid-Liquid Extraction Method Coupled with HPLC and its Application in Determining S-triazine Group of Herbicides in Soil Samples

The dispersive liquid-liquid extraction (DLLE) is an environmentally benign process, which is based on simple, sensitive and rapid sample pre-treatment technique, coupled with HPLC-UV. This unique method has been designed for the separation of s-triazine as a herbicide residue in environmental soil samples. The influencing parameters which have been used to optimize the extraction efficiency include type, extraction solvent (ES) volume, dispersive solvents (DS), extraction time (mainly centrifugation time), pH, ionic strength for the addition of different salts. Firstly, tetrachloroethane was taken as exreaction solvent (ES) to extract pesticide residues from target samples. Furthermore, acetonitrile acted as dispersive solvent in the DLLE method. The value of linearity that has been reported with concentration range of 0.05-200 mu gL(-1), and value of correlation coefficient (r) lies in between 0.9997. The recovery of the herbicide from three soil samples spiked between 20 and 100 mu gL(-1) were in the recovery in between the range 88.02% to 95.90.0% and the relative standard deviations (RSDs) were 2.7%. Limit of quantitations (LOQs) obtained in this method was 0.09 mu gL(-1). These results significantly revealed that DLLE is a very accurate and reliable method to estimate the desired pesticide, even at trace amounts, in soil samples.