Online Monitoring of Bromate in Ozonized Water Without a Previous Separation Process

Abstract

The use of ozonation for the purification of drinking water can lead to the formation of bromate. The US Environmental Protection Agency and the European Directive for human drinking water has lowered the regulatory level for bromate down to 10 microg l(-1), such that methods must be developed for monitoring the formation of bromate, particularly in on-site situations. In the present work we report a fluorometric method for the determination of bromate based on the reaction with carbostyril-124, a compound that shows fluorescence mainly at pH values above 4 and, when bromated, generates a non-fluorescent product. The reaction can thus be used as an indirect method for determination of the ion. The proposed method, which uses the flow injection (FI) technique, allows online application and kinetic control of the variables affecting the process, together with shorter reaction times, and it provides maximum sensitivity and selectivity. Under optimum conditions, it is possible to determine the analyte within the 4-200 microg l(-1) range, with a limit of detection of 0.9 microg l(-1) and a relative standard deviation (n=12, [BrO3-]=5 and 30 microg l(-1)) of 3.2% and 2.6% respectively. The determination rate was ten samples per hour.

Sequential injection spectrophotometric method for screening bromate produced as an ozonation water disinfection by-product

“…Bromate formation is particularly problematic since it is not biodegradable in the commonly use biological filters employed after the ozonation process 5 . Consequently, several methods for bromate determination, mostly in water, have been reported (Table 1) such as ion chromatography 6 , HPLC 7,8 , chemiluminescence 9 and spectrophotometric methods [10][11][12][13][14] . In most those works the application range is quite similar ranging from about 1 µg/L (0.008 µM) to about 1 mg/L (8 µM), including a couple of flow-based approaches 10,12,13 .…”

“…Consequently, several methods for bromate determination, mostly in water, have been reported (Table 1) such as ion chromatography 6 , HPLC 7,8 , chemiluminescence 9 and spectrophotometric methods [10][11][12][13][14] . In most those works the application range is quite similar ranging from about 1 µg/L (0.008 µM) to about 1 mg/L (8 µM), including a couple of flow-based approaches 10,12,13 . Therefore, without loss of sensitivity, the flow-based approaches represent a faster, effective alternative for the bromate determination as shown with quantification rate of up to 46 h -1 reported by Tóth et al 10 .…”

Fifty Years of π‐Conjugated Triaz­enes

“…Such improvements made ICCD methods time‐consuming, highly cost and also suffer from complexity and the need to deal of experience proper operation. A series of electrochemical 23, 24 and spectrophotometric methods 11, 25–33 has been reported for determination of bromate in variety of samples. A large portion of these methods were unsatisfactory as a result of their low sensitivity for monitoring trace and/or ultra trace bromate concentrations in drinking water.…”

A New Fluorescence Method for Determination of Ammonium Nitrogen in Aquatic Environment Using Derivatization with Benzyl Chloride

“…21,22 O-Phthaldialdehyde (OPA), usually used in combination with some reductants including sulfite, 23,24 2-mercaptoethanol 25,26 and n-acetyl-cysteine, 27 has been widely applied to detect ammonium due to the yield highly fluorescent isoindole derivatives. This fluorometric method is improved by combining with ion chromatography to solve interference problems and enlarge the working range, [28][29][30] but it requires expensive chromatographic equipment and a long diffusion time.…”