纳米碳纤维分离富集-电感耦合等离子体质谱法测定痕量钴和镍

Determination of cobalt and nickel by carbon nanofibers microcolumn preconcentration and inductively coupled plasma mass spectrometry

以纳米碳纤维（CNFs）为微柱吸附材料，采用电感耦合等离子体质谱（ICP—MS）法研究了CNFs对金属离子Co^2＋和Ni^2＋的吸附性能，考察了酸度、洗脱剂浓度、试样流速、共存离子等主要因素对测定的影响，确定了最佳吸附和解脱条件。实验结果表明，在pH6．0～9．0范围内，待测离子可被CNFs定量吸附，用0．5mol／LHNO。可将吸附在微柱上的待测物完全洗脱，Co^2＋，Ni^2＋在CNFs上的动态吸附容量分别为0．90mg／g和0．86mg／g。在优化的实验条件下，本法测定Co和Ni的检出限（3d）分别为0．004ng／mL和0．08ng／mL，相对标准偏差（RSD）分别为4．0％和4．8％（n=9，p=1．0ng／mL）。本法用于环境水样中痕量钴和镍的测定，回收率为94．5％～109％。

A new method was developed for the determination of trace cobalt and nickel in environmental water sample by inductively coupled plasma mass spectrometry （ICP-MS） after preconcentration with modified carbon nanofibers （CNFs） packed microcolumn. The adsorption behaviors of the analytes on CNFs were studied systematically. The influence of main factors including acidity, elution concentration,sample flow rate, co-exist ions,etc, on the determination of the analytes have been examined in detail. The studied metal ions can be adsorbed quantitatively on CNFs in the range from pH 6.0 to pH 9.0, and then eluted completely with 0.5 mol/L HNO3. The dynamic adsorption capacity of CNFs was found to be 0.90 mg/g and 0.86 mg/g for Co^2＋ and Ni^2＋ , respectively. Under the optimum conditions, the detection limits （30） of this method were 0. 004 ng/mL for Co and 0.08 ng/mL for Ni, and the relative standard deviations （RSDs） were 4.0% and 4.8%, respectively （n=9, p= 1.0 ng/mL）. The proposed method has been successfully applied to the determination of Co and Ni in the environmental water sample with the recoveries between 94.5% and 109 %.