Quantitative Determination of Organophosphorus Compounds in Hard Cheese Using Gas Chromatography Coupled With Ion Trap- Tandam Spectrometry

Organophosphorus pesticides have been used extensively especially in tropical countries to control of agricultural pests. However, much of the food we eat contain pesticide residues. Analyses of organophosphorus compounds (OP) residues are carried out worldwide because of their potential health hazardous effect on humans. In this study, hard cheese was monitored for (OP) using ion trap GCMS/MS. Fourteen Organophosphorus pesticide residues were examined (methamidophos, trichlorofon, demeton-s-methyl, diazinon, paraxon methyl, phosphamidon, chlorpyrifos methyl malaxon, fenitrothion, malathion, methidathion, bromophos-ethyl, ethion and azinophosmethyl) to determine the degree of contamination with these danger contaminants. The study included 50 samples of ripened hard cheese which were collected from different factories production batches. From the total ion chromatogram it was found that methamidophos was the first eluted compound (at 5.931 minutes) while azinophosmethyl was the last one (29.563). The linearity (r2) of each compound standard curve was not less than 0.999 except for trichlorofon, demeton-s-methyl that were (0.868 and 0.818) respectively. It was found that 4 (8%) samples were contaminated with diazinon while 2 (4%) samples only were contaminated with malathion with a total percentage of 12%.The concentrations of diazinon in the four samples were 0.030, 0.046, 0.052 and 0.021 mg/kg on whole product basis where these concentrations were 0.055, 0.90, 0.094 and 0.043 mg/kg on whole fat basis respectively. Meanwhile, the concentrations of malathion in the two samples were 0.025 and 0.073 mg/kg on whole product basis while they were 0.045 and 0.130 mg/kg on whole fat basis respectively. Egypt. J. Chem. Environ. Health, 1 (1):113-133 (2015)