Optimizing the determination of haloacetic acids in drinking waters

• Published in: Journal of Chromatography A Vol. 1035; no. 1; pp. 9 - 16
• Main Authors: Domino, Mark M, Pepich, Barry V, Munch, David J, Fair, Patricia S
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 30.04.2004; Elsevier
• Subjects: Acetates - analysis; Analysis; Analytical biochemistry: general aspects, technics, instrumentation; Analytical chemistry; Analytical, structural and metabolic biochemistry; Applied sciences; Biological and medical sciences; Chemistry; Chromatographic methods and physical methods associated with chromatography; Derivatization, GC; Diazomethane; Esterification; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General pharmacology; Haloacetic acids; Medical sciences; Methylation; Pharmacology. Drug treatments; Pollution; Reproducibility of Results; Sensitivity and Specificity; Water analysis; Water Supply - analysis; Water treatment and pollution; Haloacetic acids; Methylation; Water analysis; Derivatization, GC; Diazomethane; Gas chromatography; Drinking water; Chemical analysis; Water quality; Water pollution; Derivatization
• ISSN: 0021-9673
• DOI: 10.1016/j.chroma.2004.02.034

Three methods are currently approved by the US Environmental Protection Agency for the compliance monitoring of haloacetic acids in drinking waters. Each derivatizes the acids to their corresponding esters using either acidic methanol or diazomethane. This study was undertaken to characterize the extent of methylation of these analytes by these methods, and to fully optimize methylation chemistries to improve analytical sensitivity, precision and accuracy. The approved methods were shown to have little to no esterification efficiencies for the brominated trihaloacetic acids (HAA3). Methylation with acidic methanol was determined to be more efficient and rugged than methylation with diazomethane. A new higher boiling solvent, tertiary-amyl methyl ether, is reported which has significantly improved methylation efficiencies for HAA3. Additional modifications to the method have been made that improve method ruggedness. The revised method, EPA Method 552.3, outperforms the currently approved methods, especially for HAA3.