Water Research 36 (2002) 1089–1094 Technical note Determination of haloacetic acids in water by acidic methanol esterification–GC–ECD method Anastasia D. Nikolaou*, Spyros K. Golfinopoulos, Maria N. Kostopoulou, Themistokles D. Lekkas WaterandAirQualityLaboratory,DepartmentofEnvironmentalStudies,UniversityoftheAegean,Karadoni17, 81100Mytilene,Greece Received 4 May 2000; accepted 30 May 2001 Abstract Acidic methanol esterification followed by gas chromatography (GC) with electron capture detection (ECD) was applied for the determination of the nine haloacetic acids in water. The main advantage of this method is the use of acidic methanol as the derivatization agent instead of the hazardous diazomethane. The recoveries, estimated at concentrations ranging from 0.5 to 30 mg/l, are high for eight of the nine haloacetic acids, with the only exception being monochloroacetic acid. However, problems with this compound have been reported with diazomethane derivatization methods as well. The detection limits of the method range from 0.01 to 0.2 mg/l. r 2002 Elsevier Science Ltd. All rights reserved. Keywords: Chlorination; Haloacetic acids; Derivatization; Acidic methanol 1. Introduction Chlorination of drinking water leads to the formation of organic by-products, due to the reaction of chlorine with natural organic materials in water. Trihalo- methanes (THMs) constitute the major fraction of volatile chlorination by-products [1], whereas haloacetic acids represent a significant category of non-volatile chlorination by-products [2–16]. Under practical water treatment plant conditions, the fraction of non-volatile halogenated by-products has been reported to be three to five times greater than the one of volatiles [17]. Dichloroacetic acid and trichloroacetic acid, have been proved to be animal carcinogens [18]. Dichloroacetic acid, in particular, is believed to be a more potent carcinogen than THMs [19,20]. The category of haloacetic acids includes the follow- ing nine compounds [21]: monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), monobromoacetic acid (MBAA), dibro- moacetic acid (DBAA), tribromoacetic acid (TBAA), bromochloroacetic acid (BCAA), dichlorobromoacetic acid (DCBA) and dibromochloroacetic acid (DBCAA). In Greece and in the European Community haloacetic acids are currently not regulated. In the United States, according to the Stage I DBP Rule proposed by US. Environmental Protection Agency in 1994 [22], a maximum contaminant level (MCL) of 0.060 mg/l for the sum of concentrations of five haloacetic acids (MCAA, DCAA, TCAA, MBAA and DBAA) was obtained. This value was suggested to be reduced to 0.030mg/l according to the Stage II DBP Rule. Qualitative target levels for haloacetic acids have also been set by the World Health Organization (WHO): 50 mg/l for DCAA and 100 mg/l for TCAA [23]. In the drinking water of Greece, volatile chlorination by-products have been determined by liquid–liquid extraction [24,25], Purge and Trap [26] and closed loop stripping analysis (CLSA) [15] methods. From the non- volatile fraction only DCAA and DBAA have been *Corresponding author. Tel.: +30-25136-000(227); fax: +30-251-36226. E-mailaddress: nnikol@aegean.gr (A.D. Nikolaou). 0043-1354/02/$-see front matter r 2002 Elsevier Science Ltd. All rights reserved. PII:S0043-1354(01)00300-1