Moving towards on-line, real-time monitoring of haloacetic acids at concentrations relevant to drinking water utilities

摘要

A fully-automated preconcentration procedure for haloacetic acids (HAAs) with on-line internalrnstandardization using sequential injection analysis (SIA) is described. The SIA procedure isrnintegrated as a module with post-column reaction ion chromatography (PCR-IC) for on-line,rnreal-time analysis of HAAs in drinking water distribution systems. The method detection limitsrnfor the individual HAAs species were all less than 0.9 μg/L, an average improvement by a factorrnof 5.6 compared to previous PCR-IC analyzers. Side-by-side comparison studies of HAAsrnanalysis in 14 real-world drinking water samples from Alabama, Arkansas, Kentucky,rnMinnesota, Missouri, Mississippi, New York, Pennsylvania and Tennessee are summarized thatrncompare the SIA-PCR-IC to USEPA Method 552.3 with the bias values typically less than 5rnμg/L for eight of the nine individual HAAs. The improved signal to noise ratio of the SIA-PCRICrnallowed for evaluations of peristaltic pump tubing lifetime and the stability of thernnicotinamide reagent.