Development of a method for the determination of phthalate esters in sewage sludge including chromatographic separation from polychlorinated biphenyls, pesticides and polyaromatic hydrocarbons

Abstract

A method was developed that allows phthalate esters (PEs) to be determined in sewage sludge samples by use of gas chromatography (GC) with electron-capture detection. Discrimination of the PEs in the split injector of the GC system was detected and the resulting problems are discussed. The ultrasonic technique was optimised for extraction time and number of extractions and compared with the Soxhlet extraction technique. It was shown that extraction efficiency is slightly better with ultrasonication than using Soxhlet extraction. The Soxhlet extraction also yielded much higher blank levels. The extract clean-up was carried out by dual column liquid chromatography with neutral alumina and Florisil. In this way separation of polychlorinated biphenyls, pesticides and polyaromatic hydrocarbons from the PEs was attained. This procedure was used successfully to determine PEs in several sewage sludge samples.