Highly sensitive and selective hyphenated technique (molecularly imprinted polymer solid-phase microextraction-molecularly imprinted polymer sensor) for ultra trace analysis of aspartic acid enantiomers

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• 作者：Bhim Bali Prasad ; ^{prof.bbpd@yahoo.com} ; Amrita Srivastava ; Mahavir Prasad Tiwari ^{mahavirtiwari@gmail.coms}
• 关键词：Molecularly imprinted polymer solid-phase microextraction ; d- and l-aspartic acid ; Differential pulse anodic stripping voltammetry ; Surface grafting-from approach
• 刊名：Journal of Chromatography A
• 出版年：2013
• 出版时间：29 March, 2013
• 年：2013
• 卷：1283
• 期：Complete
• 页码：9-19
• 全文大小：1258 K

文摘

The present work is related to combination of molecularly imprinted solid-phase microextraction and complementary molecularly imprinted polymer-sensor. The molecularly imprinted polymer grafted on titanium dioxide modified silica fiber was used for microextraction, while the same polymer immobilized on multiwalled carbon nanotubes/titanium dioxide modified pencil graphite electrode served as a detection tool. In both cases, the surface initiated polymerization was found to be advantageous to obtain a nanometer thin imprinted film. The modified silica fiber exhibited high adsorption capacity and enantioselective diffusion of aspartic acid isomers into respective molecular cavities. This combination enabled double preconcentrations of d- and l-aspartic acid that helped sensing both isomers in real samples, without any cross-selectivity and matrix complications. Taking into account 6 ¡Á 10⁴-fold dilution of serum and 2 ¡Á 10³-fold dilution of cerebrospinal fluid required by the proposed method, the limit of detection for l-aspartic acid is 0.031 ng m L^?1. Also, taking into account 50-fold dilution required by the proposed method, the limit of detection for d-aspartic acid is 0.031 ng m L^?1 in cerebrospinal fluid.