Analytical Sciences

Flow-Injection Spectrophotometric Determination of Bromate in Bottled Drinking Water Samples Using Chlorpromazine Reagent and a Liquid Waveguide Capillary Cell

Ildikó V. TÓTH,* Inês C. SANTOS,** Cláudia F. M. AZEVEDO,** Jorge F. S. FERNANDES,** Ricardo N. M. J. PÁSCOA,*,** Raquel B. R. MESQUITA,**,*** and António O. S. S. RANGEL**

*REQUIMTE, Laboratório de Química Aplicada, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
**CBQF—Centro de Biotecnologia e Química Fina, Escola Superior de Biotecnologia, Centro Regional do Porto da Universidade Católica Portuguesa, Rua Dr. António Bernardino Almeida, 4200-072 Porto, Portugal
***Laboratory of Hydrobiology, Institute of Biomedical Sciences Abel Salazar (ICBAS) and Institute of Marine Research (CIIMAR), Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal

In this work, aiming to develop a simple, inexpensive method for the determination of low bromate levels in water samples, a liquid waveguide capillary cell (LWCC) was coupled to a FIA system. The long optical path (100 cm) of the LWCC was used to improve the sensitivity and the limit of detection without resorting to any off-line or in-line preconcentration processes. The spectrophotometric determination was based on the oxidation of chlorpromazine by bromate in an acidic medium, resulting in the formation of a colored radical product. Sulfamic acid was added to the reagent for minimizing the interference of nitrite, and a chelating ion exchange resin was used to remove major cationic interferences. The developed system allowed the determination of bromate within the range between 1 – 20 μg L⁻¹ with a detection limit of 0.2 μg L⁻¹.

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