Determination of chlordane in foods by gas chromatography

Chlordane comes under the group of persistent organic pollutants, which, according to the Stockholm Convention, should be completely prohibited or widely limited. Within the Environmental and Health Monitoring Programme the National Institute of Public Health in Prague, Centre for the Hygiene of Food Chains in Brno, is involved in a project, which explores the dietary exposure of the population of the Czech Republic to chemical substances. In order to meet the demands it is necessary to obtain data which would contribute to a comprehensive description of exposure doses of the priority persistent organic pollutants based on the Stockholm Convention. alpha- and gamma-chlordane and oxychlordane were incorporated into the project in 2002. Chlordane was monitored in food samples of the so-called food basket of the Czech population. After culinary treatment the food samples underwent extraction, were purified (GPC, Florisil) and analysed (GC-ECD). The method for determination of chlordanes in food was developed in our laboratory and was validated. Internal standards were used to determine the recovery of the analytical procedure. The limits of quantification depended on the type of the matrix and ranged between 0.002 and 0.05 μg kg−1. CRM 598 BCR and proficiency testing (FAPAS) are used to assure that the method provides data of required precision and accuracy. The method is accredited by the Czech Accreditation Institute. In the majority of analysed samples the content of chlordane was below the limit of quantification. The highest amount of chlordanes was found in freshwater fish (2.78 μg kg−1), butter and vegetable fat. The results of monitoring are used for estimation of the dietary exposure of the population of the Czech Republic to these substances.