Determination of Pesticide Residues in Cotton MatrixUsing LC-MS\MS and GC-MS\MS

Abstract

Name: Mahmoud Hamdy Ahmed Abd El-Wahed Title of the thesis: Determination of Pesticide Residues in Cotton MatrixUsing LC-MS\MS and GC-MS\MS Position:Chemist Degree: M.Sc., Faculty of science, Ain Shams University Public worldwide application of pesticides in crops and environment have been increased for the past several decades. The new global concept is to care about textiles and clothes safety to improve the protection of the human health and the environment from the harmful pesticide residues. Very few articles have been published for determination of several pesticide classes in cotton fibers in one multi-residue method. A simple, efficient, sensitive, accurate and reliable multi-residue method was developed for the determination of 412 residual pesticides in cotton fibers by using modified QuEChERS method with Liquid and Gas Chromatography coupled to Triple Quadrupole Mass Spectrometer (LC-MS/MS & GC-MS/MS) for qualitative and quantitative analysis according to the international standards concepts. The developed method covered several pesticide classes, including 43 carbamates, 16 pyrethroids, 27 organochlorines (OCs), 54 organophosphorus (Ops), 31 urea derivatives, 7 Polychlorinated biphenyl (PCBs), 6 Neonicotinoid and 228 other pesticides. Most of the target pesticides were listed in Oeko-Tex Standards, the EU Ecolabel for textile products, and the Egyptian recommendations of the Agricultural Pesticide Committee (APC-Egypt). The method optimization and validation were carried out according to the EU guidelines. The results were shown to be reliable where the corresponding average recoveries within the acceptable range of 70-120%; the relative standard deviations were less than 20%. The limit of quantitation (LOQ) of this method is 0.01 mg kg-1 for all pesticides except for 3 GC-compounds and 19 LC-compounds which have LOQ of 0.05 mg kg-1. the local markets in Egypt need to be monitored to evaluate the risk of these contaminants in scientific terms. Pesticide residues were determined in some cotton products that were collected from different local markets in Egypt during 2017. Among the collected cotton product samples, 14 different pesticides were detected in 20 samples in the concentration range from 0.01 to 0.416 mg kg-1 for the detected pesticides. The obtained results reflected that chlorpyrifos, malathion, profenofos and cypermethrin were the most frequently detected pesticide residues in the cotton product samples. Only one raw cotton sample has exceeded the summation of detected pesticide residues.