在线富集流动注射-光纤传感光度法测定饮用水中Cr(VI)铬的含量

摘要

Objective To determinate Cr (VI) in water samples by Flow Injection Spectrophotometry with on line preconcentration.Methods 0.50 mol/L nitric acid solution was taken as the eluent, two phenyl two carbon acyl hydrazine solution 0.16 mol/L as chromogenic agent, and cerium nitrate solution of 1×10-5 mol/L as precipitant, reaction tube length 1.50 m;the sample reagent and precipitating agent injection speed was 2 mL/min, and the accumulation time was 30 min, detection a wavelength 545 nm.Results The regression equation was: Y=0.244 8X=0.024 7, linear range: 0.05~0.50 μg/L (r2=0.998 9).The standard deviation of Cr (VI) standard with the concentration of 0.30 μg/L to 1.5%.The detection limit was 0.009 8 μg/L, and the recoveries were 98.3%;the content of Cr (VI) in the water samples:tap water, Sweet bottled water, Snow white real bottled water, Ruo Jian pakaged drinking water, Nong Fu Spring pakaged drinking water,Wa Ha Ha pakaged drinking water, Pure pakaged drinking water, Alkaoua pakaged drinking water were 0.852, 0.240, 0.185, 0.071, 0.141, 0.163, 0.051, 0.104 μg/L respectively.Conclusion The method is suitable for the determination of Cr (VI) in water samples with high sensitivity and samples without pretreatment.%目的 采用在线富集流动注射-光纤传感光度法测定水样品中Cr(VI)的含量.方法 以0.50 mol/L的硝酸溶液为洗脱液,0.16 mol/L的二苯基碳酰二肼溶液为显色剂,1.0×10-5 mol/L的硝酸铈溶液为沉淀剂,反应管长度1.50 m,样品-试剂-沉淀剂的进样速度为2.00 mL/min,富集时间为30 min,检测波长为545 nm.结果 回归方程为:Y=0.244 8X0.024 7,线性范围:0.05~0.50 μg/L(r2= 0.998 9),相对标准偏差RSD为1.5%,检测限为0.009 8 μg/L,回收率为98.3%,自来水、甜驰桶装水、雪白真桶装水、渃减瓶装水、农夫山泉瓶装水、娃哈哈瓶装水、纯水乐瓶装水、爱夸瓶装水水样品中Cr(VI)含量分别为0.852、0.240、0.185、0.071、0.141、0.163、0.051、0.104 μg/L.结论 方法灵敏度高,样品在线分析无需前处理,适用于水样品中Cr(VI)的含量测定.