الفهرس 
High-pressure liquid chromatography (HPLC)Only 14 pages are availabe for public view
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Abstract
Orange oil is considered as the largest produced essential oil worldwide due to its unique properties. Pesticide residues in orange oil are expected to be much higher than the original fruit due to orange peel’s cold-pressing during orange oil production. These residues may cause various health problems if consumed. The purpose of our study was to develop, optimize and compare four multi-residues extraction methods (dilution, QuEChERS, ethyl acetate, and mini-Luke) for analysis of 387 pesticides in orange oil using LC-MS/MS and GC-MS/MS. To our knowledge, this is the first report on the use of ethyl acetate and the mini-Luke method for the analysis of orange oil. The comparison was based on recoveries, matrix effect, and the amount of co-extract matrix. The optimum mean recoveries were obtained by the ethyl acetate method, which successfully analyzes 371 out of 387 pesticides with acceptable recovery (70-120%). It also showed a narrow recovery distribution in the range of 90-110% for 69% of all studied pesticides. Regarding the matrix effect, the QuEChERS method gave the highest number of pesticides with an insignificant matrix effect (80-120%) for both LC and GC amenable pesticides. The least amount of co-extract matrix components according to GC-MS/MS scan and gravimetric analysis has been achieved by the QuEChERS method.
In conclusion, the Ethyl acetate method gives acceptable recovery for a wide range of pesticides with a narrow recovery distribution and a moderate amount of co-extract matrix. While the QuEChERS method provides better selectivity and cleaner extract but with a narrow scope and less precision.
A monitoring program has been conducted to analyze the pesticide residues content in the orange oil sample that has been produced in Egypt using the ethyl acetate method. Thirty five orange oil samples have been analyzed and found to contain several pesticides (at least 15 pesticides) in each sample with various classes. The risk assessment to these pesticide levels couldn’t be evaluated due to the absence of MRL. The risk of this pesticide depends mainly on the manufacture dilution factor in each application.