Flow Injection Determination of Trace Bromate in Salts using Spectrophotometric Detection Directly in-Line Coupled with Anion-Exchange Separation and Preconcentration

Abstract

A flow injection (FI) system is presented for simple, rapid and sensitive determination of bromate at sub ppm levels in salts. In order to achieve highly sensitive and selective determination of bromate in salts, the anion-exchange separation/preconcentration of bromate using 1.0 M NaCl as an eluent was developed and directly in-line coupled with spectrophotometric detection at 592 nm based on the bromate oxidation of V (IV) and complex formation of resulting V (V) with Nitro-PAPS [2-(5-Nitro-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)-phenol] in a flow injection system. The present FI system offers many advantages with respect to simplicity and sensitivity, with a short analysis time (about 10 min), low limit of determination (0.05 ppm) in salts, and good reproducibility (rsd<3%). The results for analysis of commercially available sea salts (11 samples) and imported solar salts (4 samples) using the present FI system have revealed that BrO₃^-contents in all of these samples are less than 0.05 ppm.