Amperometric Sensors Based on Mercaptopyridine-Montmorillonite Intercalation Compounds

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• 作者：Montserrat Colilla ; Margarita Darder ; Pilar Aranda ; and Eduardo Ruiz-Hitzky
• 刊名：Chemistry of Materials
• 出版年：2005
• 出版时间：February 22, 2005
• 年：2005
• 卷：17
• 期：4
• 页码：708 - 715
• 全文大小：394K
• 年卷期：v.17,no.4(February 22, 2005)
• ISSN：1520-5002

文摘

The objective of this work is the study of the intercalation of 2- and 4- mercapto-substituted pyridines(2Mpy and 4Mpy, respectively) in Na⁺-montmorillonite, providing intercalation compounds withinteresting functional properties derived from the presence of the mercapto group. CHN chemical analysis,X-ray diffraction, Fourier transform infrared spectroscopy, and ¹³C NMR spectroscopy have been employedfor the characterization of the intercalation compounds. The molecular arrangement of such species inthe interlayer space depends on the intercalation medium (neutral or acidic) and on the position of themercapto group in the starting mercaptopyridine. In methanol medium, only 4Mpy can be intercalated,the pyridine ring interacting with the interlayer cations through water bridges. 2Mpy and 4Mpy can beintercalated by cation exchange from the corresponding protonated (pyridinium) derivatives, formed byaddition of 1 M HCl to the intercalation medium. Tautomeric equilibrium between thiol and thione speciesof such mercaptopyridines must be taken into account to explain the arrangement of molecular aggregatesand their particular orientation in the interlayer space. We have tried to correlate the structural arrangementsof the intercalated species with the complexing ability of mercapto groups toward heavy metal ions. Inthis way, these materials have been tested as the active phase of carbon paste electrodes (CPEs) for theamperometric determination of Cd(II), Pb(II), Cu(II), and Hg(II) ions in aqueous solutions. CPEs basedon pure 2- or 4-mercaptopyridines alone do not give an electroanalytical response toward heavy metalions, whereas CPEs of the nanostructured materials show good electroanalytical behavior due to theparticular arrangement of the guest species in the interlayer space of the clay.