茜素红-十六烷基三甲基溴化铵催化动力学光度法测定痕量铬(Ⅵ)  

Determination of trace chromium(Ⅵ) by catalytic kinetic spectrophotometry with alizarin red-cetyltrimethyl ammonium bromide system

作　　者：沈淑君[1] 邹小勇[2] 

机构地区：[1]漳州职业技术学院食品与生物工程系,福建漳州363000 [2]中山大学化学与化学工程学院,广东广州510275

出　　处：《冶金分析》2013年第12期47-51,共5页Metallurgical Analysis

摘　　要：在pH 5.0的HAc-NaAc缓冲溶液介质中,以增敏剂十六烷基三甲基溴化铵（CT-MAB）及活化剂邻菲啰啉（phen）共同作用下,Cr（Ⅵ）对过氧化氢氧化茜素红（ARS）褪色有明显的催化作用,建立了动力学光度法测定痕量Cr（Ⅵ）的新方法,并研究了影响催化褪色反应的因素.在选定的实验条件下,非催化反应体系与催化反应体系最大吸收波长均为553 nm,Cr（Ⅵ）的质量浓度在0.001～0.10 μg/mL呈良好的线性关系,回归方程为：△A =9.404ρ（μg/mL）-0.020 7,相关系数r=0.998 1,检出限为0.80 ng/mL.方法应用于水样及土壤样品中铬（Ⅵ）的测定,结果与原子吸收光谱法相符,相对标准偏差（RSD,n=6）为1.7％～3.0％.In pH 5. 0 HAc-NaAc buffer solution medium, with cetyl trimethyl ammonium bromide （CTMAB） as sensitizer and phenanthroline （phen） as activator, Cr （Ⅵ） had a significant catalytic effect on the oxidizing discoloration reaction between alizarin red （ARS） and hydrogen peroxide, so a novel method for the determination of trace Cr（Ⅵ） was established by kinetic spectrophotometry and the in- fluence factors on the catalytic discoloration reaction were examined. Under the selected experimental conditions, the non-catalytic reaction system and the catalytic system had the same maximum absorp- tion wavelength at 553 nm, and Cr（Ⅵ） in the concentration range of 0. 001-0.10 μg/mL showed a good linear relationship. The regression equation was △A = 9.40ρ （μg/mL） -- 0. 020 7 with correlation coefficient r = 0. 998 1 and detection limit of 0.80 ng/mL. The method was applied to the determina- tion of chromium in water and soil samples. The results were consistent with those obtained by atomic absorption spectrometry, and the relative standard deviation （RSD, n=6） was 1.7%-3.0%.

关 键 词：催化动力学光度法 茜素红 铬(Ⅵ) 水 土壤 

分 类 号：O657.32[理学—分析化学]