Determination of organochlorine pesticides by GC-ECD and GC-MS-MS techniques including an evaluation of the uncertainty associated with the results

The pesticides lindane, vinclozolin, aldrin, p,p'DDE, o,p'DDT, pp'DDT, methoxychlor, kepone and mirex, which are classified as endocrine disrupters, have been analysed. This was conducted within an extensive hospital-based epidemiological study that includes surgically treated breast cancer patients and a matching group of women with no sign of estrogenic-dependent disease. Patients were from the Hospital Torrecardenas and living in agricultural areas of Almeria (Spain). The results from the analysis of 100 serum samples were performed by gas chromatography (GC) with electron capture detection (ECD) and tandem mass spectrometry (MS-MS) detection mode. Performance characteristics, such as linearity, detection limit (LOD) and quantitation limit (LOQ), together with an estimate of measurement uncertainty (using validation data) is presented for each pesticide, in both chromatographic methods. The results obtained were compared. The advantage of MS-MS over ECD to determine endocrine disrupting compounds in complex matrix was also shown. p,p'DDE was the most frequently encountered pesticide, as well as the one found at higher concentration level. p,p'DDT was found in eight samples. Lindane was detected at low concentration level. While vinclozolin, aldrin, methoxychlor, kepone, o,p'DDT and mirex were absent in all samples analysed.