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A Method for Selecting Structure-switching Aptamers Applied to a Colorimetric Gold Nanoparticle Assay
Published on: February 28, 2015
Smartphone-assimilated colorimetric sensor for sub-nanomolar emamectin detection via KA30 capped silver nanoparticles
Aziz Balouch1, Kashif Hussain1, Ayman Nafady2
1HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, 75270, Pakistan.
Abstract:
In this report, we firstly synthesized nitro calix [4] resorcinarene compound (referred as KA30) and characterized it though proton (1H) nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS) and Fourier Transform Infra-red (FTIR) spectroscopy. KA30 was applied as functionalizing agent for the formation of silver nanoparticles (KA30-AgNPs). These NPs were confirmed as highly selective and extremely sensitive colorimetric sensor for ultra-low level detection of emamectin (EMA) as a novel report. Significant aspect of the sensor is its unique detection range between 0.0005 and 29.5 μM via color change from yellow to colorless with hypochromic-bathochromic shift exhibiting limit of detection (LOD) and limit of quantification (LOQ) as 0.12 nM and 0.4 nM respectively. The sensor was applied to colorimetrically and optically detect EMA in real samples of serum, urine and food. The sensor was further allied with smartphone for real-time, and on-site detection of EMA and results were validated through UPLC.
