A review on solid phase micro extraction-high performance liquid chromatography (SPME-HPLC) analysis of pesticides

Pesticides are an important and diverse environmental and agricultural species. Their determination in formulations, in feed and food, and in complex environmental matrices (e.g., water, soil, sludge, sediments, etc.) often requires separation methods capable of high efficiency, unique selectivity, and high sensitivity. Because pesticides (organophosporus, organochlorine, carbamate, dithiocarbamate, etc.) are carcinogenic, they are problematic for humans in the course of the food chain. Residual analyses have been performed to find out the concentration and type of pesticides and their metabolites left in food at the time of consumption. This ultimately helps in production of better and human-friendly pesticides. A new and effective sampling technique, Solid-Phase microextraction (SPME), was developed in 1990 using a fused silica fiber coated on the outside with appropriate stationary phase in which analyte in the sample is directly extracted to the fibber coating. Two types of fiber techniques can be used to extract analytes: Headspace (HS-SPME), where the fiber is exposed to the vapor phase above a gas, and direct immersion (DI-SPME), where the fiber is directly immersed in the samples. More advanced in-tube SPME recently has been developed, which uses open tubular fused-silica capillary column instead of SPME fiber. SPME in combination with HPLC, GC, GC-MS, LC-MS is getting a wide acceptability as an analytical technique. These have great advantages over the classical sampling techniques, which are time consuming and require larger samples and solvents. This review discusses the various advantages and disadvantages of the SPME for the extraction of the pesticides and their analysis by HPLC.