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Spectrophotometric flow injection procedure for the on-line monitoring of sulphite in high ionic strength brine
journal contributionposted on 1991-01-01, 00:00 authored by P MacLaurin, P J Worsfold, A Townshend, Neil BarnettNeil Barnett, M Crane
A spectrophotometric flow injection procedure for the determination of sulphite in potassium chloride brine is described. The reagent used was the organic disulphide 2,2′-dinitro-5-5′-dithiodibenzoic acid and the effect of the reaction pH on the kinetics is discussed. A laboratory method for the determination of sulphite in the range 0.1-20 mg l-1 is presented for three matrices; water, standard potassium chloride solutions and potassium chloride brine. The robustness of the method is discussed in terms of sample pH, sample temperature and potassium chloride concentration. A modified procedure for on-line analysis with a linear range of 3-100 mg l-1 is described and the results are compared with those obtained off-line by iodimetric titration. The relative standard deviation for 168 results (triplicate determinations of a 62.3 mg l-1 sulphite standard) over a 7 d cycle was 2.1%. Results are also presented for a 21 d on-line trial.