Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
Anal Chim Acta. 2012 Apr 20;723:54-60. doi: 10.1016/j.aca.2012.02.027. Epub 2012 Feb 23.
Cd(II) imprinted 3-mercaptopropyltrimethoxysilane (MPTS)-silica coated stir bar was prepared by sol-gel technique combining with a double-imprinting concept for the first time and was employed for stir bar sorptive extraction (SBSE) of trace Cd(II) from water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. A tetramethoxysilane (TMOS) coating was first in situ created on the glass bar surface. Afterward, a sol solution containing MPTS as the functional precursor, ethanol as the solvent and both Cd(II) and surfactant micelles (cetyltrimethylammonium bromide, CTAB) as the template was again coated on the TMOS bar. The structures of the stir bar coating were characterized by FT-IR spectroscopy. Round-bottom vial was used for the extraction of Cd(II) by SBSE to avoid abrasion of stir bar coatings. The factors affecting the extraction of Cd(II) by SBSE such as pH, stirring rate and time, sample/elution volume and interfering ions have been investigated in detail, and the optimized experimental parameters were obtained. Under the optimized conditions, the adsorption capacities of non-imprinted and imprinted coating stir bars were found to be 0.5 μg and 0.8 μg bar(-1). The detection limit (3σ) based on three times standard deviations of the method blanks by 7 replicates was 4.40 ng L(-1) and the relative standard deviation (RSD) was 3.38% (c=1 μg L(-1), n=7). The proposed method was successfully applied for the analysis of trace Cd(II) in rain water, East Lake and Yangtze River water. To validate the proposed method, certified reference material of GSBZ 50009-88 environmental water was analyzed and the determined value is in a good agreement with the certified value. The developed method is rapid, selective, sensitive and applicable for the analysis of trace Cd(II) in environmental water samples.
Cd(II)印迹的 3-巯丙基三甲氧基硅烷（MPTS）-二氧化硅涂层搅拌棒是通过溶胶-凝胶技术结合双印迹概念首次制备的，用于搅拌棒吸附萃取（SBSE）水样中的痕量 Cd(II)，然后用电感耦合等离子体质谱（ICP-MS）检测。首先在玻璃棒表面原位形成四甲氧基硅烷（TMOS）涂层。之后，将含有 MPTS 作为功能前体、乙醇作为溶剂以及 Cd(II)和表面活性剂胶束（十六烷基三甲基溴化铵，CTAB）作为模板的溶胶溶液再次涂覆在 TMOS 棒上。搅拌棒涂层的结构通过傅里叶变换红外光谱（FT-IR）进行了表征。圆底瓶用于通过 SBSE 萃取 Cd(II)，以避免搅拌棒涂层的磨损。详细研究了影响 SBSE 萃取 Cd(II)的因素，如 pH 值、搅拌速率和时间、样品/洗脱体积和干扰离子，并获得了优化的实验参数。在优化条件下，非印迹和印迹涂层搅拌棒的吸附容量分别为 0.5 μg 和 0.8 μg bar(-1)。基于 7 个重复的方法空白的 3 倍标准偏差，检测限（3σ）为 4.40 ng L(-1)，相对标准偏差（RSD）为 3.38%（c=1 μg L(-1)，n=7）。该方法成功应用于雨水、东湖和长江水中痕量 Cd(II)的分析。为了验证该方法，对 GSBZ 50009-88 环境水标准物质进行了分析，测定值与证书值吻合良好。所开发的方法快速、选择性好、灵敏度高，适用于环境水样中痕量 Cd(II)的分析。
