Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo, Spain.
Talanta. 2011 Oct 15;85(5):2361-7. doi: 10.1016/j.talanta.2011.07.092. Epub 2011 Aug 3.
A new flow injection (FIA) procedure for the preconcentration of cadmium in urine using multiwalled carbon nanotubes (MWCNT) as sorbent and posterior electrothermal atomization atomic absorption spectrometry (ETA-AAS) Cd determination has been developed. Cadmium was retained in a column filled with previously oxidized MWCNTs and it was quantitatively eluted with a nitric acid solution. The parameters influencing the adsorption-elution process such as pH of the sample solution, amount of sorbent and flow rates of sample as well as eluent solutions have been studied. Cd concentration in the eluent was measured by ETA-AAS under the optimized conditions obtained. The results indicated the elimination of urine matrix effect as a consequence of the preconcentration process performed. Total recovery of cadmium from urine at pH 7.2 using a column with 45 mg of MWCNTs as sorbent and employing a HNO(3) 0.5 mol L(-1) solution for elution was attained. The detection limit obtained was 0.010 μg L(-1) and the preconcentration factor achieved was 3.4. The method showed adequate precision (RSD: 3.4-9.8%) and accuracy (mean recovery: 97.4-100%). The developed method was applied for the determination of cadmium in real urine samples from healthy people (in the range of 0.14-2.94 μg L(-1)) with satisfactory results.
一种新的流动注射（FIA）程序，用于使用多壁碳纳米管（MWCNT）作为吸附剂预浓缩尿液中的镉，并用电热原子化原子吸收光谱法（ETA-AAS）测定 Cd。镉被保留在填充有预先氧化的 MWCNT 的柱中，并通过硝酸溶液定量洗脱。研究了影响吸附-洗脱过程的参数，例如样品溶液的 pH 值、吸附剂的量和样品以及洗脱溶液的流速。在优化条件下，通过 ETA-AAS 测量洗脱液中 Cd 的浓度。结果表明，由于进行了预浓缩过程，消除了尿液基质效应。使用 45mg MWCNT 作为吸附剂的柱，在 pH 7.2 下从尿液中回收镉的总回收率达到 0.5 mol L（-1）HNO（3）溶液。获得的检测限为 0.010μg L（-1），实现的预浓缩因子为 3.4。该方法具有良好的精密度（RSD：3.4-9.8%）和准确性（平均回收率：97.4-100%）。该方法已应用于测定健康人尿液中镉的含量（范围为 0.14-2.94μg L（-1）），结果令人满意。
