Yebra M C, Cancela S
Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Anal Bioanal Chem. 2005 Jun;382(4):1093-8. doi: 10.1007/s00216-005-3237-x. Epub 2005 May 21.
Cadmium was continuously extracted with diluted nitric acid from legumes and dried fruit samples using a simple, rapid and continuous ultrasound-assisted extraction system. A minicolumn packed with a chelating resin (Chelite P, with aminomethylphosphoric acid groups) was placed between the extraction unit and the detector for cadmium preconcentration. The cadmium content in the acid extract was retained into the minicolumn, and elution was carried out with hydrochloric acid, with this trace metal continuously monitored by flame atomic absorption spectrometry. An experimental design (Plackett-Burman 2(6) x 3/16) was used to optimize the continuous leaching procedure and the preconcentration step. The method allowed a total sampling frequency of 10 and 14 samples per hour for legumes and dried fruit, respectively. The procedure displayed good precision (2.0 and 2.5%, respectively, expressed as relative standard deviations) for samples containing 0.202+/-0.005 microg g(-1) Cd (broad bean) and 0.239+/-0.004 microg g(-1) Cd (peanut). Detection limits of 0.014 microg g(-1) Cd for 60 mg of legume samples and 0.011 microg g(-1) Cd for 80 mg of dried fruit samples were obtained. The method was successfully applied to the determination of trace amounts of cadmium in legumes and dried fruit samples.
使用简单、快速且连续的超声辅助萃取系统，用稀硝酸从豆类和干果样品中连续萃取镉。在萃取单元和用于镉预浓缩的检测器之间放置一个填充有螯合树脂（Chelite P，含氨甲基磷酸基团）的微型柱。酸萃取液中的镉含量保留在微型柱中，用盐酸进行洗脱，通过火焰原子吸收光谱法对这种痕量金属进行连续监测。采用实验设计（Plackett - Burman 2(6) x 3/16）来优化连续浸出程序和预浓缩步骤。该方法分别允许每小时对豆类和干果进行10个和14个样品的总采样频率。对于含有0.202±0.005 μg g⁻¹镉（蚕豆）和0.239±0.004 μg g⁻¹镉（花生）的样品，该程序显示出良好的精密度（分别表示为相对标准偏差为2.0% 和2.5%）。对于60 mg的豆类样品，获得的检测限为0.014 μg g⁻¹镉；对于80 mg的干果样品，检测限为0.011 μg g⁻¹镉。该方法成功应用于豆类和干果样品中痕量镉的测定。
