Analysis of polychlorinated biphenyls, pyrethroid insecticides and fragrances in human milk using a laminar cup liner in the GC injector

Since 1970 the State Laboratory of Basle City has been periodically analyzing human milk from the region (the latest in 1998/99) as a bioindicator for the environmental load of organochlorine pesticides [1, 2]. The analysis of human milk is very complex including several clean-up steps and is therefore time consuming. The focus is mainly on organochlorine pesticides, polychlorinated biphenyls (PCB), and nitro-musk compounds; analytes which are easily detectable with gas chromatography and electron capture detection (ECD). Our aim was to minimize the clean-up steps for the analysis of ECD sensitive substances. Furthermore, analytes insensitive to EC detection that require MS detection, such as polycyclic musk substitutes, were of interest. With the help of a specially designed GC liner in the vaporizing injector of the gas chromatograph, the laminar cup liner, we have considerably reduced the time and effort in the sample preparation. With the described clean-up procedure we analyzed 53 human milk samples from the region of Basle for PCB, pyrethrins, and pyrethroid insecticides and fragrances (nitro-musk compounds and polycyclic musk substitutes). While PCB showed a general downward trend in mean concentrations since 1980, residues of the polycyclic musk substitutes galaxolide and tonalide were detectable in almost every sample (e.g., 73 mug/kg fat of HHCB, 74 mug/kg fat of AHTN). Pyrethrins and pyrethroid insecticides were detected only at low concentrations between 0.03 and 0.46 mg/kg fat.