Two chromatographic methods for the quantitative determination of some pesticides applied for cucumber pests in Egypt

Two novel sensitive and accurate thin‐layer chromatography and high‐performance liquid chromatography methods were used for monitoring the residues of four pesticides: mandipropamid, metalaxyl, thiophenate methyl and carbendazim, which are widely used to eliminate cucumber pests in Egypt. The first method is a thin‐layer chromatography method, using silica gel plates as a stationary phase and hexane/methanol/acetone/glacial acetic acid (7.5:2:0.5:0.1, v/v) as a developing system. The second method is high‐performance liquid chromatography using isocratic elution and a mobile phase consisting of acetonitrile/0.02 molar potassium dihydrogen phosphate buffer (25:75, v/v) at a flow rate of 1 mL min−1 with UV detection at 225 nm. All the obtained results were evaluated regarding the agricultural committee of Egypt and showed acceptable pesticides residues.