UNDERSTANDING THE CHEMISTRY THAT IS APPLIED IN THE DETECTION OF DBPs BY THE CAPILLARY MEMBRANE SAMPLING-FLOW INJECTION ANALYSIS METHOD

摘要

In 1974, it was discovered that chlorinated organic disinfection by-products (DBPs) are formed as a result of excessive chlorination. The two most commonly monitored classes of DBPs are the trihalomethanes (THMs) and the haloacetic acids (HAAs). The THMs include chloroform (CHCl3), bromodichloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl) and bromoform (CHBr3). These four compounds are collectively referred to as THM4. The HAAs include monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), monobromoacetic acid (MBAA) and dibromoacetic acid (DBAA). These five compounds are referred to as HAA5. Concern about the adverse health effects of THMs and HAAs in the water supply led to the Safe Drinking Water Act, which set maximum contaminant levels (MCLs) of the DBPs in drinking water. The United States Environmental Protection Agency (USEPA) has established a maximum contaminant level (MCL) in finished drinking water for total THM4 and total HAA5 at 0.080 mg/L and 0.060 mg/L, respectively.