Development of a method of analysis for pentachlorophenol in liver

Pentachlorophenol (PCP) has been used for many years as an all purpose fungicide and pesticide. Its widespread use, especially in the wood preservation industry, has led to there being detectable levels within the food chain. It is therefore necessary to be able to detect and quantify levels present in plants and animals to ensure that tolerance is met. Detectable levels of PCP have been found in the liver of pigs in the Netherlands by the Food Inspection Service, Amsterdam in the range 0.01- 1.2 mg/kg (median 0.06 mg/kg). It was the purpose of this project to optimise the procedure for the quantification of PCP in the liver of cattle, sheep and chickens. Much of the work has been done on improving the efficiency of the derivatisation step. Parameters that appear to have no influence on the efficiency of the derivatisation step are the age and volume of acetic anhydride used, the temperature of and the time taken for the derivatisation procedure, the amount of Na2SO4 used in the drying step. Parameters that have an influence on the efficiency of the derivatisation step are the order in which the components are added together (acetic anhydride should be added to the mixture of the sample and the K2C03 ) , and the volume and the molarity of the K2C03. The optimum result was obtained using 80 ml 0.1M K2C03. The derivatised PCP (dPCP) was stable in the injector of the gas chromatography (GC) system, also during storage in the refrigerator for at least one month. Recovery experiments with liver spiked at the 1 mg/kg level show results better than 80 % (CV 2.5 % (n=3)) The coefficient of variation for the repeatability in a liver at the 0.05 mg/kg level was 18.8 % (n=6) and at the 0.01 mg/kg level 55.3 % (n=4).