College of Chemical Engineering, Sichuan University, Chengdu, 610065, PR China.
Analyst. 2011 Nov 7;136(21):4580-6. doi: 10.1039/c1an15502d. Epub 2011 Sep 16.
In this work, a simple, rapid and sensitive UV-visible spectrophotometric technique for the determination of copper based on injection-ultrasound-assisted dispersive liquid-liquid microextraction (IUSA-DLLME) was developed, using sodium diethyl-dithiocarbamate (Na-DDTC) as a complexing agent. The fabrication of a home-made microporous plastic tip was first reported, and by using it, contamination from a metallic tip was avoided; moreover cloudy solutions were easily obtained. Several parameters were investigated including the extraction solvent type and volume, pH of the reaction solution, concentration of DDTC, salt addition, reaction time and temperature, and sonication and centrifugation time. The results showed that carbon tetrachloride was a better extraction solvent. Under the optimal conditions, the calibration curve was linear in the range of 0.5-50 ng mL(-1) of copper with a R(2) of 0.9996. The relative standard deviation (RSD) for the determination of 0.5 ng mL(-1) copper was ±3.3% (n = 7), and the detection limit (3Sbc/m) was 0.05 ng mL(-1) in the original solution. An enrichment factor of 222 was obtained. The developed method was validated by analysis of a certified reference solution and applied successfully to the determination of copper in tap water, bottled pure water and river water. The advantages of the IUSA-DLLME method are simplicity of operation, rapidity, low cost, low LOD and high enrichment factor.
在这项工作中，开发了一种基于注射超声辅助分散液-液微萃取（IUSA-DLLME）的简单、快速和灵敏的紫外可见分光光度法测定铜，使用二乙氨基二硫代甲酸钠（Na-DDTC）作为络合剂。首次报道了自制微孔塑料尖端的制备，使用该尖端可避免金属尖端的污染；此外，很容易得到混浊溶液。研究了几种参数，包括萃取溶剂类型和体积、反应溶液的 pH 值、DDTC 浓度、盐的添加、反应时间和温度以及超声和离心时间。结果表明，四氯化碳是一种更好的萃取溶剂。在最佳条件下，铜的浓度在 0.5-50ng mL(-1)范围内呈线性关系，相关系数（R(2)）为 0.9996。测定 0.5ng mL(-1)铜的相对标准偏差（RSD）为±3.3%（n=7），在原始溶液中检测限（3Sbc/m）为 0.05ng mL(-1)。获得了 222 的富集因子。该方法通过对认证参考溶液的分析进行了验证，并成功应用于自来水中、瓶装纯净水中和河水中铜的测定。IUSA-DLLME 方法的优点是操作简单、快速、成本低、LOD 低和富集因子高。
