Clo2 Residual Testing Method
CHLORINE DIOXIDE AND CHLORITE
105
7. ANALYTICAL METHODS
The purpose of this chapter is to describe the analytical methods that are available for detecting, measuring, and/or monitoring chlorine dioxide and chlorite, its metabolites, and other biomarkers of exposure and effect to chlorine dioxide and chlorite. 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
No methods for determining chlorine dioxide in biological materials were located. Most studies concerning human health effects measure the concentrations of chlorine dioxide in the air or in water. The measurement of chlorine dioxide in biological materials is not commonly used because of the rapid conversion of chlorine dioxide to chlorine-containing metabolites, such as chlorite and chloride ions. Abdel-Rahman et al. (1980b) developed a method to quantitatively and qualitatively measure the metabolites of chlorine dioxide (e.g., ClO2-, and ClO-) in biological fluids. These biomarkers can be used to indirectly measure chlorine dioxide exposure. The concentration of residual chlorite ion in vegetables and eggs treated with sodium chlorite was determined by UV-ion chromatography (Suzuki et al. 1997). Sodium chlorite was extracted with water and cleaned-up using C18 cartridge. The detection
105
7. ANALYTICAL METHODS
The purpose of this chapter is to describe the analytical methods that are available for detecting, measuring, and/or monitoring chlorine dioxide and chlorite, its metabolites, and other biomarkers of exposure and effect to chlorine dioxide and chlorite. 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
No methods for determining chlorine dioxide in biological materials were located. Most studies concerning human health effects measure the concentrations of chlorine dioxide in the air or in water. The measurement of chlorine dioxide in biological materials is not commonly used because of the rapid conversion of chlorine dioxide to chlorine-containing metabolites, such as chlorite and chloride ions. Abdel-Rahman et al. (1980b) developed a method to quantitatively and qualitatively measure the metabolites of chlorine dioxide (e.g., ClO2-, and ClO-) in biological fluids. These biomarkers can be used to indirectly measure chlorine dioxide exposure. The concentration of residual chlorite ion in vegetables and eggs treated with sodium chlorite was determined by UV-ion chromatography (Suzuki et al. 1997). Sodium chlorite was extracted with water and cleaned-up using C18 cartridge. The detection