Analytical Methods for Determination of Regulated and Unregulated Disinfection By-Products in Drinking Water: A Review.

Abstract

Chlorine is a household name as a drinking water disinfectant. Incidentally, its application often results in the formation of toxic products generally called disinfection by-products (DBPs) some of which are halonitromethanes (HNMs), haloacetonitriles (HANs), trihalomethanes (THMs), halo acetic acids (HAAs). Similarly, the use of ozone, chloramine and chlorine dioxide for water treatment results in the formation of emerging unregulated DBPs) such as nitrosodimethylamine (NDMA), and other nitrogen -containing DBPs known to be more toxic than the regulated DBPs. Because DBPs are absolutely soluble in water, less stable and volatile at high temperature during analysis, no common method is available for the analysis of these chemicals. In view of this analytical challenge there is the need to review the existing methods. The aim of this study is to present a survey of the existing methods used for the analysis of DBPs in drinking water with a view to identifying their limitations and suggest the possible ways of method improvement. The review identifies environmental unfriendliness of the commonly used solvent methyl tert-butyl ether (MBTE), the fibre used in the dispersive liquid–liquid microextraction (DLLME) continues to be a source of impurity to the analyte. The analytical instrument with high sensitivity and robust library database is essential in the analysis and overall identification of DBPs.