铜试剂修饰的纳米TiO_2分离富集ICP-AES测定铜、铅、锌的研究

Preconcentration of diethyldithiocarbamate modified nanometer-TiO_2 and the determination of Cu,Pb and Zn with ICP-AES

建立了在表面活性剂(十二烷基硫酸钠)的活化作用下,铜试剂修饰的纳米TiO2分离富集,电感耦合等离子体原子发射光谱(ICP-AES)测定Cu2+、Pb2+和Zn2+的新方法。考察了溶液pH、洗脱条件和干扰离子等因素对分析物分离富集的影响。结果表明,在pH 4.0,Cu2+、Pb2+和Zn2+可被铜试剂修饰的纳米TiO2定量富集,吸附的金属离子可用2.0 mL0.10 mol/L HCl溶液完全洗脱。在优化的实验条件下,铜试剂修饰的纳米TiO2对Cu2+、Pb2+和Zn2+的吸附容量分别为6.2,18.6和6.9 mg/g。本法对Cu2+、Pb2+和Zn2+的检出限(3σ)分别为:0.32,1.68和0.39 ng/mL,相对标准偏差(RSD)分别为3.4%、3.7%和4.8%(n=11,c=50 ng/mL)。本法应用于环境样品和黄芪标准样品(GBW 10028)中Cu2+、Pb2+和Zn2+的测定,测定值与标准值基本吻合,分析结果满意。

Nanometer TiO2 was modified with diethyldithiocarbamate under the activation of surfactant（SLS） and used for preconcentration of trace metal ions.The adsorption behavior of Cu（Ⅱ）,Pb（Ⅱ） and Zn（Ⅱ） on nanometer TiO2-diethyldithiocarbamate was investigated.At pH 4.0,Cu（Ⅱ）,Pb（Ⅱ） and Zn（Ⅱ） were retained on the nanometer TiO2-diethyldithiocarbamate,then eluted with 2 mL 0.10 mol/L HCl and determined by ICP-AES.The adsorption capacity of modified nanometer TiO2-diethyldithiocarbamate was found to be 6.2,18.6 and 6.9 mg/g for Cu（Ⅱ）,Pb（Ⅱ） and Zn（Ⅱ）,respectively.The precision（R.S.D.） and the detection limit（3σ） of the method were 3.4%,3.7%,4.8%（n=11,c=50 ng/mL） and 0.32,1.68,0.39 ng/mL,respectively.The method was ensured by analyzing standard reference material（GBW 10028）,the results obtained is in good agreement with standard values.This method was successfully applied to the determination of trace Cu（Ⅱ）,Pb（Ⅱ） and Zn（Ⅱ） in environmental samples with satisfactory results.