Development of new methodologies for on-line determination of the bromate ion in samples of water subjected to ozonation treatment.
The bromate ion has been identified as an inorganic disinfection by-product (DPB) in water subjected to purification treatment. Its presence arises from the application of oxidation processes to water containing bromide through the action of oxidant agents such as the ozone used in ozonation processes. This ion has been identified as a possible carcinogen by the U.S. Environmental Protection Agency, which recommends a maximum concentration of 10 microgL(-1). The literature reports a broad range of methods for the analysis of bromate in water, among which ion chromatography is the one most widely used, with different detection systems. However, most of the methods described to date require state-of-the-art technology and costly instrumentation, such that they are not readily adaptable to routine analyses. The present work reports a procedure for the spectrophotometric determination of bromate based on the bromination reaction of 3-3' dimethoxybenzidine, o-dianisidine (ODA). The reaction is based on the formation of Br2 in the presence of excess bromide and the later bromination of ODA, generating a product that absorbs at 450 nm. The procedure was set up with Flow Injection Analysis and allows the determination of the analyte in the 8 microg L(-1)-3.3 mg L(-1) range, with a detection limit of 6.0 microg L(-1) and relative standard deviations (n=12, [BrO3-]=8.0 and 30.0 microg L(-1)) of 4.8% and 2.9%, respectively. The determination rate was 10-11 samples/hour.
Almendral
María-Jesús
MJ
Departamento de Química Analítica, Nutrición y Bromatología, Faculty of Chemistry, University of Salamanca, Plaza de la Merced s/n, E-37008, Salamanca, Spain. almendral@usal.es
Alonso
Angel
A
Fuentes
María-Socorro
MS
D000327:Adsorption; D001959:Bromates / Q000032:analysis*; D001966:Bromine / Q000737:chemistry; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D003962:Dianisidine / Q000737:chemistry; D017022:Flow Injection Analysis / Q000379:methods; D007477:Ions; D057230:Limit of Detection; D009862:Online Systems; D010126:Ozone / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014881:Water Supply / Q000032:analysis*
D001959:Bromates; D007477:Ions; D014867:Water; D010126:Ozone; D003962:Dianisidine; D001966:Bromine