Rapid and Inexpensive Densitometric Method, Using TLC Plates, for Quantification and Determination of Nine Pesticides in Water

Nine pesticides of commonly used in Gaza Strip were tested in this work for optimal separation onto silica gel TLC plates in acetone/ cyclohexane, 1:2 (v/v), as a mobile phase to develop a new densitometric method for quantification and determination of these pesticides in water samples. These pesticides are: abamectine, atrazine, benomyl, cymoxanil, diuron, imidacloprid, linuron, penconazole, and propazine. Calibration plots were linear between 25 to 1000 ng/spot for all pesticides with a correlation coefficient, r, between 0.9920 and 0.9993. Recoveries after enrichment of real water samples on Bakerbond RP-C18cartridges were between 79.4 and 103.7 % at a relative standard deviation between ± 1.92 and 3.68 %. Detection limits LOD of 25 - 100 ng per spot for eight of the pesticides were reached, which meet the European limits for pesticides in drinking water (100 ngL^-1 ), while penconazole has an LOD value of 200 ngL^-1 because of its low UV-absorption coefficient.