acents We highlight the unique properties of nanomaterials as solid contacts. acents We describe potentiometric sensors based on ionophore-modified nanomaterials. acents We present recent developments in nanomaterial-based potentiometric biosensors.
A novel N-pyridin-2-ylmethylsuccinamic acid-functionalized smectite nanomaterial was synthesized by immobilizing of N-pyridin-2-ylmethylsuccinamic acid through chemical bonding onto (3-aminopropyl) triethoxysilane modified smectite. The structural, thermal, morphological and surface properties of raw, silane-grafted and the N-pyridin-2-ylmethylsuccinamic acid-functionalized smectites were investigated by various characterization techniques. The thermal analysis data showed the presence of peaks in the temperature range from 200 degrees C to 600 degrees C due to the presence of physically adsorbed silanes, intercalated silanes, surface grafted silanes and chemically grafted silane molecules between the smectite layers. The powder x-ray diffraction patterns clearly indicated that the aminopropyl molecules also intercalated into the smectite interlayers as bilayer arrangement whereas N-pyridin-2-ylmethylsuccinamic acid molecules were only attached to 3-aminopropyltriethoxysilane molecules on the external surface and edges of clay and they did not intercalate. Fourier transform infrared spectroscopy confirms N-pyridin-2-ylmethylsuccinamic acid molecules bonding through the amide bond between the amine group of aminopropyltriethoxysilane molecules and a carboxylic acid functional group of N-pyridin-2-ylmethylsuccinamic acid molecules. The guest molecules functionalized onto the smectite caused significant alterations in the textural and morphological parameters of the raw smectite.
Nanomaterials play an important role in the fabrication of chemosensors and biosensors, due to their unique physical and chemical properties, such as large surface area/volume ratio, good conductivity, excellent electrocatalytic activity and high mechanical strength. We review recent advances in the applications of these nanomaterials in potentiometric sensors. We highlight the development of stable solidstate polymeric membrane ion-selective electrodes (ISEs). We describe ISEs based on ionophore-modified nanomaterials. Also, we present highly-sensitive potentiometric biosensors based on nanomaterials. (C) 2013 Elsevier Ltd. All rights reserved.