The spectrophotometric determination of chromium and vanadium with ortho-dianisidine

Ariel, M.; Manka, J.

doi:10.1016/0003-2670(61)80154-2

Cited by 4 publications

(1 citation statement)

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“…3 Benzidine dyes act as prochromophores; the actual chromophores are produced by a redox reaction between the analyte and the benzidine dye. In the past, this approach has been applied to the quantitation of higher valence metal oxyanions, e.g., chromate 4,5 and vanadate, 5 as well as non-metal oxidants, e.g., N-bromosuccinimide, 6 hydrogen peroxide, 7 and periodic acid. 8 Most recently, DMB has been used for the spectrophotometric determination of the disinfection byproduct bromate (BrO 3…”

Section: Aim Of Investigationmentioning

confidence: 99%

Influence of reagent purity on the ion chromatographic determination of bromate in water using 3,3′-dimethoxybenzidine as a prochromophore for photometric detection

Urbansky

Brown

2000

J. Environ. Monitor.

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Variable availability of the purified dihydrochloride salt of 3,3'-dimethoxybenzidine (DMB; ortho-dianisidine) led us to investigate the effects of reagent purity on the analytical results obtained when this reagent is used in the photometric determination of the disinfection byproduct bromate. After analyte ions are separated by ion chromatography, a solution of DMB (post-column reagent) is added to the eluate and the DMB is oxidized, thereby producing a chromophore detected by its absorbance. Although some commercial products of undefined grade performed well, others did not. Variability was also observed between lots of purified material. Sensitivity at low concentrations (< 5 micrograms L-1 BrO3-) varied by a factor of up to 10. In some cases, the lower limit of detection for photometric detection was greater than that obtained using conductivity detection, as high as 5-7 micrograms L-1 BrO3-. An impurity or several impurities are suspected to be responsible for deviations from linearity at low analyte concentrations. This investigation underscores the need for ensuring reagent purity in environmental analyses. Ideally, chemical manufacturers will meet the needs of analytical chemists who test potable water and begin producing a high grade material in sufficient quantities to meet monitoring requirements. The establishment of third-party standards for a spectrophotometric grade of DMB.2HCl would be helpful in ensuring that a variety of manufacturers could supply products of uniformly high quality that would be suitable for the measurement of bromate in public drinking water supplies.

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