221 HEXACHLOROCYCLOHEXANE 7. ANALYTICAL METHODS

The purpose of this chapter is to describe the analytical methods that are available for detecting, measuring, and/or monitoring α-, β-, γ-, and δ-HCH, its metabolites, and other biomarkers of exposure and effect to α-, β-, γ-, and δ-HCH. The intent is not to provide an exhaustive list of analytical methods. Rather, the intention is to identify well-established methods that are used as the standard methods of analysis. Many of the analytical methods used for environmental samples are the methods approved by federal agencies and organizations such as EPA and the National Institute for Occupational Safety and Health (NIOSH). Other methods presented in this chapter are those that are approved by groups such as the Association of Official Analytical Chemists (AOAC) and the American Public Health Association (APHA). Additionally, analytical methods are included that modify previously used methods to obtain lower detection limits and/or to improve accuracy and precision. 7.1 BIOLOGICAL MATERIALS The α-, β-, γ-, and δ-isomers of HCH, and/or their phenolic metabolites have been measured in biological samples such as adipose tissue, serum, urine, milk, semen, and the brain by gas chromatographic methods listed in Table 7-1. The most commonly used methods for measuring α-, β-, γ-, and δ-HCH in serum, semen, adipose tissue, and milk are gas chromatography (GC) or high-resolution gas chromatography (HRGC) combined with electron capture detection (ECD) and mass spectrometry (GC/MS) (Barquet et al. 1981; Burse et al. 1990