GC/MS determination of phenolic compounds in soil samples using Soxhlet extraction and derivatization techniques.

are certain that a number of synthetic chemicals act like hormones (e.g. estrogen) and interact with the human hormone system. Scientists also agree that the magnitude of the problem (including human exposure) is uncertain. Therefore, the analysis of phenols in natural wastewater and soils is of prime importance to environmental organizations due to their frequent occurrence in a wide range of industrial waste and natural water. They are toxic and have an effect upon aquatic organism including bioaccumulation in the tissue of fish. 1 Numerous energy-related industries produce alkyl phenols as by-products in the manufacture and use of petrochemical products. 2 For example, 4-nonylphenol has an estrogenic effect in nature, which can cause the feminization of male fish, resulting in a lack of reproductive success. 3 Bisphenol A has been found in a diverse range of products like the interior coatings of cans and drums, etc., 4 water main filters, artificial teeth, nail polish and food packaging materials. 5 In addition, the environmental pollution of soil by phenols and pesticides is a major environmental concern. Many methods for determining hexachlorobenzene and pentachlorophenol in soil samples have been reported. 6–9 A method for Bisphenol A in water was also developed. 10 Recently, we reported a successful application of the liquid-liquid extraction method for determining endocrine disruptors in different water samples. 11 Moreover, an on-column silylation method for the analysis of phenols in water samples using solid phase micro-extraction has been reported in our laboratory. 12 In this paper, a GC-MS method for the determination of total phenols from soil samples using Soxhlet extraction is reported. Extraction from soil was done with dichloromethane. A derivatization step was carried out with BSTFA. The silylate derivative was analyzed by gas chromatography-mass spectrometry. Experimental Reagents and standards The phenolic compounds studied were: 4-t-butylphenol, 2,4-dichlorophenol, 4-pentylphenol, 4-hexylphenol, 4-t-octylphenol, 4-heptylphenol, 4-nonylphenol, 4-octylphenol, pentachloro-phenol and bisphenol. All of the phenols were supplied by Kanto and TIC chemicals (Tokyo, Japan). Standard solutions (1000 ng/ml) of each compound were mixed and prepared in dichloromethane (DCM) and stored in a refrigerator. Working solutions were prepared weekly by diluting these solutions with DCM. Internal standard solutions (100 ng/ml) of anthracene, naphthalene and fluorene were prepared with DCM; N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) was supplied by Wako Pure Chemical Industries, Ltd. (Osaka, Japan). BSTFA was used as a derivatization reagent. All solutions were stored in dark bottles and refrigerated. Gas chromatography–mass spectrometry The details of the …