Application of HPLC-DAD and TLC-DAD after SPE to the Quantitative Analysis of Pesticides in Water Samples

Abstract

Abstract The objective of this work is to present a new procedure for the analysis of pesticides in water samples with use of solid phase extraction (SPE) and high performance chromatography with diode array detection (HPLC-DAD) and thin layer chromatography with diode array scanning (TLC-DAD). Pesticides were enriched from lakes water samples by solid phase extraction (SPE) on C18/SDB-1, C18, C18 Polar Plus, and CN cartridges. SPE was used not only for preconcentration of analytes but also for their fractionation. The analytes were eluted with methanol, and next with dichloromethane. Methanol eluates were analysed by HPLC-DAD, the dichloromethane eluates with TLC-DAD. The method was validated for precision, repeatability, and accuracy. The calibration plots were linear between 0.1 and 50.0 µg mL−1 for all pesticides, the correlation coefficients, r, were between 0.9992 and 1.000, as determined by HPLC-DAD. In the TLC experiments, the best fit for the calibration lines was found when the calibration data were analyzed using a second degree polynomial regression. Calibration plots lay between 0.1 and 17 µg spot−1 for all pesticides, the correlation coefficients, r, were between 0.9974 and 0.9997, as determined by TLC-DAD. The limit of detection (LOD) was between 0.04 and 0.65 µg spot−1 (TLC-DAD) and between 0.02 and 1.56 µg mL−1 (HPLC-DAD).