【摘要】 借助量子化学计算,从分子层面模拟了γ-环糊精（γ-CD）主体与L-半胱氨酸（L-Cys）氧化产物客体之间的超分子相互作用,得到γ-CD与L-Cys氧化产物之间的弱相互作用能EL（-12. 6 e V）,其与D-Cys氧化产物客体的弱相互作用能（E_D=-2. 7 e V）相差3. 7倍,分子内氢键键价相差近1倍.据此,构建了基于手性源γ-环糊精的阻抗型传感器,并用于L-Cys的阻抗识别.结果表明,以铁氰化钾（Ⅱ/Ⅲ）作为氧化还原探针分子,电化学阻抗信号变量(R_et)与L-Cys浓度在0. 1～1. 0μmol/L（阶段一）和1. 0～6. 0μmol/L（阶段二） 2个范围内分别呈现良好的线性关系,检出限为74 nmol/L（S/N=3）.与未修饰玻碳电极相比,L-Cys在该手性传感器上的阻抗响应灵敏度提高了约19倍,对含巯基结构相似物的选择性明显提高;将该传感器应用于人体血清、药品胶囊样品的分析,平均回收率在88. 9%～108%之间.建立了一种新颖、低成本、简便的针对弱电活性手性化合物的定量识别方法,为其电化学分析提供了新策略.更多还原

【Abstract】 By means of quantum chemical calculation,the supramolecular interaction between the γ-cyclodextrin（ γ-CD） as the host and the L-cysteine（ L-Cys） oxidation product as the guest was simulated from the molecular level. The weak interaction energy（ EL） between γ-CD and L-Cys oxidation product reaches-12. 6 eV,which is 3. 7 times different from the interaction between γ-CD and D-Cys oxidation product（ E_D=-2. 7 eV）. Their intramolecular hydrogen bonds exist nearly doubled difference. Based on the theoretical simulation,an γ-CD modified impedance sensor was constructed for sensitive and specific impedance identification of L-Cys. Using potassium ferricyanide（ Ⅱ/Ⅲ） as the redox probe,the electrochemical transfer impedance( R_et)linearly changed with the concentration of L-Cys between 0. 1 μmol/L and 1. 0 μmol/L（ stage one）,and from1. 0 μmol/L and 6. 0 μmol/L（ stage two）,with the detection limit of 74 nmol/L（ S/N = 3）. Compared with the unmodified glassy carbon electrode,the sensitivity for the impedance response of L-Cys has been increased about 19 times. Meanwhile,the selectivity to the thiol-containing structural analog is significantly improved by this cyclodextrin-based sensor,successfully applied for the detection in human serum and drug capsules with average recoveries between 88. 9% and 108%. This study establishes a novel,low-cost,simple,quantitative identification method for chiral compounds with weak electrical property,providing a potential strategy for electrochemical analysis of chiral targets.更多还原