Identification of unknown peaks in foods during residual pesticide analysis

Four unknown peaks were detected in GC chromatograms during analysis of organophosphorus pesticide residues in foods. They were identified by using GC/MS as triethyl phosphate (TEP), tributyl phosphate (TBP), diphenyl 2-ethylhexyl phosphate (DPEHP) and N-ethyltoluenesulfoneamide (NETSA), which are used as plasticizers or flame retardants in food packaging. These chemical substances were detected in the range of tr. (below 0.01 microg/g) to 11 micro/g from 29 samples, and they were also detected in the packaging. It was supposed that they were transferred to the foods from the packaging. Furthermore, they were detected in some cereals and cereal products which contain fat and had been preserved for a long time.