改性纳米TiO2分离富集-ICP—AES法测定环境样品中痕量铬、铜、镍和铅

提出了改性纳米TiO2分离富集电感耦合等离子体原子发射光谱（ICP—AES）法测定环境样品中痕量Cr3＋、Cu2＋、Ni2＋和Pb2＋的新方法。系统地研究了溶液pH值、吸附剂用量、洗脱条件、流速、静态吸附容量和干扰离子等因素对分析物分离富集的影响。结果表明，在pH4．0，Cr3＋、Cu2＋、Ni2＋和Pb2＋可被改性纳米TiO2定量富集，吸附的金属离子可用2．0mL2．5mol·L^-1 HCl溶液完全洗脱。在优化的实验条件下，吸附剂对Cr3＋、Cu2＋、Ni2＋和Pb2＋的吸附容量分别为18．1，17．6，23．2和26．8mg·g-1。本法对Cr3＋、Cu2＋、Ni2＋和Pb2＋的检出限（30）分别为：0．25，0．43，0．62，0．39ng·mL-1，相对标准偏差（RSD）分别为2．3％，3．1％，2．5％，3．8％（n=11）。方法用于环境样品中痕量Cr3＋、Cu2＋、Ni2＋和Pb2＋的测定，结果令人满意。

ICP-AES determination of trace Cr, Cu, Ni and Pb in environmental sample preconcentrated by modified nano-TiO2

Nano-Ti2 was used for preconcentration of trace heavy metal ions Cr3＋ , Cu2＋ , Ni2＋ and Pb2＋ in enviromental samples and ICP-AES was used for simultaneous determination. The effects of pH, absorbent volume, elution condition, flow rate static adsorption capacity and the interference ions on the concentrating of analytes were investigated. The results showed that at pH 4.0, Cr3＋ , Cu2＋ , Ni2＋ and Pb2＋ could be retained on the modified nano-Ti2, and then eluted with 2.0mL 2.5mol/L HCl completely. Under optimized experimental conditions, the adsorption capacities of modified nano-Ti2 were found to be 18.1, 17.6, 23.2 and 26.8mg/g for Cr3＋ , Cu2＋ , Ni2＋ and Pb2＋ , respectively. The detection limits （3a） were 0.25, 0.43, 0.62 and 0.39mg/mL, and RSDs were 2.3%, 3.1%, 2.5% and 3.8% （n=ll） for Cr3＋ , Cu2＋ , Ni2＋ and Pb2＋ , respectirely.