On-line solid-phase extraction and high performance liquid chromatography for the determination of bromide

Abstract

In the chromatographic determination of bromide at mg/l level, problems are faced due to interference of chloride and high acidity usually present in real samples. These problems are obviated in the present study by a combination of solid-phase extraction and HPLC. The pre-column reaction of bromide with 2-iodosobenzoic acid and. acetanilide to form 4-bromoacetanilide has been coupled to on-line pre-concentration and clean-up of derivative by solid-phase extraction using C₁₈ sorbent. Pre-concentration of up to 50 ml of sample (without any breakthrough of 4-bromoacetanilide from extraction cartridge) and transfer of total extract, rather than an aliquot of it, on to the analytical column allows achievement of a high sensitivity. High concentrations of ionic impurities including chloride as found in salts, concentrated hydrochloric acid and sea water, which interfere in conventional ion chromatography for bromide, can be tolerated. The proposed method (limit of detection of 0.2 mg/l bromide) has been applied for analysis of real samples such as salts, conc. HCl, and sea water.