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In this study, the time-dependent reaction between 11-mercaptoundecanoic acid (11-MUA) and 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide (EDC/NHS) is precisely characterized using surface enhanced infrared absorption spectroscopy (SEIRAS). According to the high correlation between the spectral results of SEIRAS and the electrochemical behavior, it strongly demonstrates that the EDC/NHS reaction would be obviously interfered by phosphate ions in the neutral pH condition (pH = 7.0)., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A sensing platform based on the attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) technique and immobilized aptamer has been proposed herein for the selective detection of mercury ions (Hg 2+ ). In the proposed platform, 5' thiolated 32-mer DNA probes with methylene blue at the 3' end were immobilized on a thin gold (Au) surface layer. Following Hg 2+ ions interacting with T bases of the aptamer, T-Hg-T bonds are formed; resulting in a hairpin-shaped formation of the DNA and a detectable change in the IR absorbance of the sensing interface. Notably, the background noise produced by external molecules (e.g., water, non-specific binding molecules and bulk solution) is reduced to a negligible level by means of the ATR detection mode. It is shown that the proposed sensor has a linear response (R 2  = 0.986) with high sensitivity and good selectivity over the Hg 2+ range of 0.01 μM-50 μM., (Copyright © 2018 Elsevier B.V. All rights reserved.)