Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
Talanta. 2011 Aug 15;85(2):1166-73. doi: 10.1016/j.talanta.2011.05.039. Epub 2011 May 27.
The poly(N-isopropylacrylamide) (PNIPA) gel is a widely studied thermo-responsive material that exhibits discontinuous change in volume when the external temperature is increased. In this paper, PNIPA gel was prepared and applied as a novel polymer coating for fiber-in-tube capillary microextraction of trace Co, Ni and Cd followed by on-line ICP-MS detection. The PNIPA coating was synthesized by using ethylene triethoxysilane (ETEOS) as the cross-linking agent under acidic conditions. This siloxane incorporated PNIPA gel achieves a dramatically rapid response rate when the external temperature is changed. The micro-structure of PNIPA coating was examined by scanning electron micrograph (SEM). Various experimental parameters including pH, temperature, sample flow rate and volume, elution solution and interfering ions affecting the extraction of the target analytes have been carefully investigated and optimized. Under the optimized conditions, the limits of detection were 0.45, 4.6 and 6.9 ng L(-1) for Co, Ni and Cd, respectively. With a sampling frequency of 13 h(-1), the relative standard deviations (RSDs) for Co, Ni and Cd were 4.8, 5.1 and 6.4% (C=1 μg L(-1), n=7), respectively. The proposed method had been successfully applied to the determination of Co, Ni and Cd in human urine. To validate the proposed method, certified reference materials of NIES No. 10-b rice flour and GBW07601 (GSH-1) human hair were analyzed and the determined values were in a good agreement with the certified values. The PNIPA coated fiber-in-tube capillary can be reused for more than 150 times without decreasing the extraction efficiency.
聚 N-异丙基丙烯酰胺（PNIPA）凝胶是一种广泛研究的温敏材料，当外部温度升高时，其体积会发生不连续变化。在本文中，我们制备了 PNIPA 凝胶并将其用作新型聚合物涂层，用于纤维-管内毛细管微萃取痕量 Co、Ni 和 Cd，随后进行在线 ICP-MS 检测。在酸性条件下，使用乙烯三乙氧基硅烷（ETEOS）作为交联剂合成了 PNIPA 涂层。当外部温度发生变化时，这种含有硅氧烷的 PNIPA 凝胶实现了极快的响应速度。通过扫描电子显微镜（SEM）检查了 PNIPA 涂层的微观结构。仔细研究并优化了各种实验参数，包括 pH、温度、样品流速和体积、洗脱溶液和干扰离子，以影响目标分析物的萃取。在优化条件下，Co、Ni 和 Cd 的检出限分别为 0.45、4.6 和 6.9 ng L(-1)。在 13 h(-1) 的采样频率下，Co、Ni 和 Cd 的相对标准偏差（RSD）分别为 4.8%、5.1%和 6.4%（C=1 μg L(-1)，n=7）。该方法已成功应用于人尿中 Co、Ni 和 Cd 的测定。为了验证该方法，分析了 NIES No. 10-b 大米粉和 GBW07601（GSH-1）人发的标准参考物质，测定值与证书值吻合良好。PNIPA 涂层纤维-管内毛细管可重复使用 150 次以上，而不会降低萃取效率。
