甲基橙退色光度法测定饮水中溴酸根离子

SPECTROPHOTOMETRIC DETERMINATION OF BROMATE BY DECOLOURING METHYL ORANGE

在三氯乙酸介质中,以溴化钾为催化剂,研究了BrO3-氧化甲基橙退色的最佳条件.以510 nm为甲基橙退色溶液的测定波长,KBrO3在0.01-0.2μg/mL范围内,甲基橙退色溶液的吸光度值与溴酸钾含量显著相关,相关系数R2=0.9993,检测限为3.8×10-3μg/mL,试样测定结果的相对标准偏差(RSD)为<8%,试样加标回收率为86.9%-99.5%.

A sensitive spectrophotometric method for the determination of bromate ion is described. The method is based on the decrease in color of aqueous methyl orange by bromate ion in acidic conditions （ Cl3CCOOH ） to produce a colored species at the maximum absorption wavelength 510nm. The method is suitable for bromate ion determination in the 0.01 μg/mL - 0.2 μg/mL range （ R^2 = 0. 9993 ）. The limit of detection is 3.8 × 10 ^-3 μg/mL and the relatively standard variance of the method is 〈 8 %. The recovery for bromate added in tap water were 86.9% -99.5%.