科研之友
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摘要
An automated method based on an optosensor included in a multisyringe flow injection system was developed for the determination of bromate in waters for human consumption. The optosensor was based on the formation of a colored radical cation after oxidation of chlorpromazine by bromate and its selective uptake in a mixed-mode cation exchanger sorbent (Discovery DSC-MCAX), placed on a flow-through spectrophotometric cell. In-line regeneration was attained by methanol + 5% (v/v) ammonia, fostering the application of the same sorbent portion up to 180 determinations. Parameters affecting the reaction development and uptake of the colored compound were studied and optimized, while in-line addition of sulfite (%26gt;= 0.100 g L-1) prevented interference from hypochlorite. The proposed methodology allowed the determination of bromate up to 50.0 mu g L-1, with 0.9 mg L-1 as the limit of detection, meeting the requirements of current EU and USA legislation. Application to real drinking water samples was successful, with a mean recovery of 100.2 +/- 2.8% for spiked levels of 5.0, 10.0 and 25.0 mu g L-1. Repeatability was good (RSD %26lt; 3.6%, n = 10) with a determination throughput of 8 h(-1), fostering the application to on-line control of water disinfection processes.
- 出版日期2012-5
