Non-dioxin-like and dioxin-like polychlorinated biphenyls in butter sampled from the Polish retail market.

The aim was to investigate levels of polychlorinated biphenyls (PCBs) in butter available on the Polish retail market. A gas chromatography-based method was developed for the purpose of this study. An ion-trap mass spectrometer was used as a detection system with high-resolution chromatography. Recoveries of individual PCBs from spiked samples varied from 58% to 105% with a recovery relative standard deviation in the range 3-16%. Levels of eight non-dioxin-like and twelve dioxin-like congeners were determined. Toxic equivalent factors (TEQs) were calculated using World Health Organization (WHO) TEQs. The average concentration of the sum of six PCBs (28, 52, 101, 138, 153, and 180) was found to be 1561±728 pg g(-1) (fat) and the upper-bound concentrations of dioxin-like congeners were (1 standard deviation uncertainty) 0.441±0.384 pg PCB-TEQ g(-1) (fat).