Kinetic-spectrophotometric method for the determination of trace amounts of bromide in seawater

Abstract

A novel simple, sensitive and rapid kinetic-spectrophotometric method is proposed for the determination of trace amounts of bromide. The method is based on its catalytic effect on the oxidation of methylene blue (MB) by hydrogen peroxide in strongly acidic solution. The oxidation reaction is activated by large amounts of chloride and can be monitored spectrophotometrically by measuring the decrease in the absorbance of MB at 746 nm. The determination of bromide is performed by a fixedtime method at the first 100 s from the initiation of the reaction. Unlike other kineticspectrophotometric methods for the determination of bromide, the proposed method does not require heating the solution. Bromide can be determined in the range from 80 to 960 µg l -1 with the detection limit of 35 µg l -1 . The relative standard deviation of ten replicate determination of 480 µg l -1 bromide was 1.4%. The influence of potential interfering ions was studied. The proposed method was satisfactorily applied to the determination of bromide in seawater without interfering effect from chloride ion.

Determination of trace amounts of bromide by flow injection/stopped-flow detection technique using kinetic-spectrophotometric method

“…In the presence of small quantities of bromide, MB is slightly oxidized by H 2 O 2 in strongly acid solution to form an oxidized product of MB. The effect of bromide on the catalytic reaction is enhanced in the presence of large amounts of chloride [19]. This can causes a rapid color changed of MB from blue to less bluish, which can be monitored spectrophotometrically at 746 nm.…”

“…Moreover, they suffer from long times due to the necessity of the sample preparation steps. Several kinds of kinetic-spectrophotometric methods based on the catalytic effect of bromide on coloration reactions with organic compounds have been reported [11][12][13][14][15][16][17][18][19]. In these methods, manual procedures for kinetic measurements are tedious and time-consuming, and are sometimes complicated.…”

“…Uraisin et al [19]. The analytical method was based on the catalytic effect of bromide on the oxidation of methylene blue (MB) with hydrogen peroxide in strongly acidic solution.…”

Automatic flow analysis procedure for the determination of bromide in L-alanine by chemiluminescence detection

“…Procedures for bromide determination in different matrices employing potentiometry, 4,5 ion exchange chromatography, 6 capillary electrophoresis, 7 spectrophotometry [8][9][10][11] have been proposed. Generally, spectrophotometric methods present adequate sensitivity, nevertheless the time consumed to perform an analysis is very long.…”

Spectrophotometric determination of bromide in water using the multisyringe flow injection analysis technique coupled to a gas-diffusion unit

“…3 According to the Environmental Protection Agency (EPA), a high dose of Br À might cause adverse effects on human health. 2,19 MB is a thiazine type dye used for dyeing fabrics and as a stain in medicine, bacteriology, and microscopy. 5 The determination of Br À in environmental samples has been reported using high performance liquid chromatography, 6 ion chromatography, 7,8 inductively coupled plasma-mass spectrometry, 9 gas chromatography, 10,11 capillary electrophoresis 12 and using a Br À ion-selective electrode.…”