碘—淀粉法比色测定岩矿中微量溴

Spectrophotometric Determination of Bromide in Rocks and Soils with Iodine-starch Method

目前测定岩矿中微量溴还没有合适的化学方法。虽然比色测溴方法很多,但灵敏度低,国外有不少催化比色测定岩矿中微量溴的报导,国内也作了很多工作,但测定条件苛刻,不易掌握。物理方法中,中子活化法被认为是灵敏度最高的方法,也是国内外常用的测定岩矿中溴含量的方法,但成本高,国内不易普遍开展。

A method was proposed for the determination of Br^(-)in rocks and soils.The sample was fused with sodium hydroxide and the water extract of the melt was passed through 717 anion exchange column,0.5 mol/L NaNO_(3)as eluent.CrO_(4)^(-)was eliminated by adding ammomium ferrous sulphate.Br-was determined by iodine-starch spectrophotometry.Beer’s law was obeyed over the range 0.5-20μg Br-/28 ml.The molar absorptivity is 9.0×10^(4)l·ml^(-1).cm^(-1).