ABSTRACT:

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.