engleski

SPE - Microwave-assisted extraction coupled system for the extraction of pesticides from water samples

Solid-phase extraction (SPE) is a commonly applied technique for preconcentration of pesticides from water samples. Microwave-assisted extraction (MAE) technique is the extraction applied for preconcentration of different compounds from solid samples. SPE coupled with MAE is capable of preconcentrating this compound from water samples too. This investigation was aimed at improving the efficiency of atrazine, alachlor and  -cypermethrin pesticides extraction from the spiked water samples applying SPE followed by microwave-assisted extraction (MASE). In this way, MAE served for elution of pesticides from C18-extraction discs with solvent heated by microwave energy. Various elution conditions were tested for their effects on extraction efficiency of the SPE-MAE combined technique. Several parameters, such as elution solvent volume (mL), elution temperature (°C) and duration of elution (minute), affect extraction efficiency of the SPE-MAE coupled system and need to be optimized for the selected pesticides. In order to develop mathematical model, fifteen experiments were performed in the central composite design. The equation was then used to predict recoveries of the pesticides under specific experimental conditions. Optimization of microwave extraction was accomplished using genetic algorithm approach. Best results were achieved using 20 mL of ethanol at 60°C. Optimal hold time was 5 minutes and 24 sec. The SPE-MAE combination was also compared with the conventional SPE extraction technique with elution of a nonpolar or a moderately polar compound with nonpolar solvents.

Solid-phase extraction (SPE) ; Microwave-assisted extraction (MAE) ; Pesticides ; Water ; Thin-layer chromatography (TLC) ; Genetic algorithm (GA)

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