Polymer synthesis and characterization of a molecularly imprinted sorbent assay for atrazine
Polymer synthesis and characterization of a molecularly imprinted sorbent assay for atrazine
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阿特拉津分子印迹吸附剂测定的聚合物合成和表征
DOI：
10.1021/jf00054a002
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发表时间：
1995
影响因子：
6.1
通讯作者：
L. Stanker
中科院分区：
文献类型：
--
作者：
M. Muldoon;L. Stanker
分子印迹技术利用在“印迹”分子存在下形成的官能化聚合物，用于开发针对印迹分子本身或结构相似的印迹分子的结合测定（Wulff，1984，1986）。分子印迹的合成涉及Sellergen和Andersson（1990）概述的几个步骤。首先，将功能化单体与它们共价和/或非共价结合的打印分子混合。接下来，该“印刷组件”与过量的交联剂共聚，形成刚性聚合物。然后从聚合物中提取或水解打印分子。据推测，印迹分子的分子印迹识别归因于官能团在聚合物基质内形成符合印迹分子的特定空间排列（Wulff和Schauhoff，1991）。此外，形状选择性空腔也可以有助于结合，特别是与非功能性印刷分子如芳烃的结合（Dunkin等人，1993年）。常用的聚合物基质使用官能单体甲基丙烯酸（MAA）和乙二醇二甲基丙烯酸酯（EGDMA）作为交联单体[例如，O'Shannesseyet al.（1989），Andersson et al.（1990）和Vlatakis et al.（1993）]。然而，已经使用了其他矩阵。例如，弱碱性官能单体已用于结合含氧印刷分子（Ramstrom等人，1993年），而具有芳香族官能度的单体已用于结合平面芳香族化合物（Dunkin等人，1993年）。分子印迹的性质通常使用色谱系统如高效液相色谱（HPLC）和薄层色谱（TLC）来研究，其中聚合物用作固相。将该方法应用于糖（Wulff和Schauhoff，1991）和氨基酸衍生物（Sellergren等人，1985; Matsiu等人，1993; Kriz等人，1994年）。受体结合测定用于研究分子印迹（Sellergren和Andersson，1990; Wulff和Schauhoff，1991），并导致分子印迹吸附测定（MIA）的发展（Vlatakis等人，1993年）。该MIA是一种放射性测定法，在竞争结合测定法中使用分子印迹聚合物作为受体。MIA与市售的两种药物（茶碱和地西泮）的免疫测定法一样灵敏。分子印迹技术比抗体生产更便宜，并且在抗体生产成本过高或抗体性能存在问题的情况下可能提供替代方案。此外，分子印迹聚合物与抗体（或其他生物受体）不同，对有机溶剂的影响非常敏感。因此，分子印迹可用于分析高度亲脂化合物（例如，PCB或二恶英），无论是在样品净化步骤中还是在检测方法中。本研究的总体目的是评估分子印迹技术用于分析农业或环境重要性的分析物。选择s-三嗪除草剂莠去津（见图1）作为研究的模型系统。它是一种具有两个仲氨基的含氮杂环，已被证明在有机溶剂中与乙酸形成复合物（韦尔豪斯和Bleam，1993年）。因此，莠去津应在相同条件下（即在有机溶剂中）与功能单体MAA结合。s-三嗪是这些研究的良好模型，因为它们相对便宜，无毒且稳定。因此，在一个典型的反应中所需的克数可以是…
Molecular imprinting technology utilizes functional-ized polymers formed in the presence of a “print” molecule for developing binding assays for the print molecule itself or a structurally similar one (Wulff, 1984, 1986). Thesynthesis of molecular imprints involves several steps as outlined bySellergen and Andersson (1990). First, functionalized monomers are mixed with the print molecule to which theybind covalently and/or noncovalently. Next, this “print assembly” is copo-lymerized with excess cross-linking agent, forming a rigid polymer. The print molecule is then extracted or hydrolyzed from the polymer. It is hypothesized that molecular imprint recognition of the print molecule is attributed to theformation of functional groups in a particular spatial arrangement within the polymer matrix conforming to that of the print molecule (Wulff and Schauhoff, 1991). In addition, shape-selective cavities may also contribute to binding, particularly with nonfunctional print molecules such as aromatic hydrocarbons (Dunkin et al., 1993). A commonly used polymer matrix uses the functional monomer methacrylic acid (MAA) with ethylene glycol dimethylacrylate (EGDMA) as the cross-linking monomer [eg., O’Shannesseyet al.(1989), Andersson et al.(1990), and Vlatakis et al.(1993)]. However, other matrices have been used. For example, weakly basic functional monomers have been used for binding oxygen-containing print molecules (Ramstrom et al., 1993), while monomers with aromatic functionalities havebeen used for binding planar aromatics (Dunkin et al., 1993). The properties of molecular imprints have often been studied using chromatographic systems such as high-performance liquid chromatography (HPLC) and thinlayer chromatography (TLC), in which the polymer is used as the solid phase. This approach was applied to the separation of racemic mixtures of sugars (Wulff and Schauhoff, 1991) and amino acid derivatives (Sellergren et al., 1985; Matsiu et al., 1993; Kriz et al., 1994). Receptor binding assays were used to study molecular imprints (Sellergren and Andersson, 1990; Wulff and Schauhoff, 1991) and resulted in the development of the molecularly imprinted sorbent assay (MIA)(Vlatakis et al., 1993). This MIA was a radioassay that used a molecularly imprinted polymer as the receptor in a competition binding assay. The MIA was as sensitive as a commercially available immunoassay for the two drugs of interest (theophylline and diazepam). Molecular imprinting technology is less expensive than antibody production andmay offer an alternative in situations when the cost of antibody production is prohibitive or antibody performance is a problem. In addition, molecular imprint polymers are highly resis-tant to organic solvent effects, unlike antibodies (or other biological receptors). Thus, molecular imprints may have applications for the analysis of highly lipo-philic compounds (eg, PCBs or dioxins) either in a sample cleanup step or in a detection method. The overall purpose of this research is to evaluate molecular imprinting techniques for the analysis of analytes of agricultural or environmental importance.The s-triazine herbicide atrazine (see Figure 1) was chosen as a model system for study. It is a nitrogenous heterocycle possessing two secondary amino groups and has been shown to form complexes with acetic acid in organic solvent (Wellhouse and Bleam, 1993). Therefore, atrazine should bind to the functional monomer MAA under the same conditions (ie, in an organic solvent). The s-triazines are good models for these studies because they are relatively inexpensive, non-toxic, and stable. Thus, the gram quantities necessary in a typical reaction can be …