Pb^(2+)-TTA-偶氮磺Ⅲ高灵敏反应用于测定食品添加剂中的Pb  

Spectrophotometric determination of lead in food additives with bromo-sulphonea Ⅲ and thenoyltrifluoroacetone

作　　者：袁莉[1] 任小娜[1] 马永钧[1] 

机构地区：[1]西北师范大学化学化工学院,兰州730070

出　　处：《分析试验室》2006年第11期23-26,共4页Chinese Journal of Analysis Laboratory

摘　　要：研究了3,6-双(4-溴-2-磺基-苯偶氮)-4,5-二羟基-2,7-萘二磺酸(溴代磺酸偶氮Ⅲ)、噻吩甲酰三氟丙酮(TTA)与Pb(Ⅱ)的显色反应。结果表明,Pb(Ⅱ)与溴代磺酸偶氮Ⅲ、TTA形成1∶1∶1的蓝绿色络合物,其最大吸收波长为659.8nm,络合物的表观摩尔吸光系数ε=6.42×105L.min-1.cm-1,Pb量在0~2.49μg/mL范围内符合比耳定律,检出限为5.27×10-3μg/mL,相对标准偏差(RSD)为0.4%~4.4%(n=5)。该方法灵敏度高,操作简便,用于市售色素和香精样品中铅的测定,加标回收率为84.96%~100.5%。The chromogenic reaction involving Pb（ Ⅱ ）, Bromo-sulphonea Ⅲ （Br-SAZ Ⅲ ） and thenoyltrifluoroacetone （TTA） was investigated. The results showed that a blue complex of Pb（ Ⅱ ）, Br-SAZ Ⅲ and TI＇A was formed with a molar ratio of 1 ： 1 ： 1. The molar absorptivity was 6.42 × 10^5 L·mol^- 1· cm^- 1 With the maximum absorption peak at 659.8 nm, the proposed procedure was used for quantitation of Pb（ Ⅱ ） in the concentration range of 0 - 62.3 μg in 25 mL with the detection limit （3s） of 5.27 × 10^-3 μg/mL. The relative standard deviations （RSD） were 0.4% 4.4% （ n = 5）. Under the optimized conditions, total lead in food additives was successfully determined with recoveries of 84.96% - 100.5%.

关 键 词：溴代磺酸偶氮Ⅲ TTA 铅 分光光度法 色素 香精 

分 类 号：O657.32[理学—分析化学]