Article ID Journal Published Year Pages File Type
1230783 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2017 7 Pages PDF
Abstract

•Simple colorimetric determination of AZT using unmodified silver nanoparticles•Aggregation of AgNPs upon addition of AZT caused rapid colour change from yellow to purple.•The method was linear in the concentration range of 0.2–100.0 μM for non-chromophoric drug AZT.•Successful in determining AZT in pharmaceuticals and spiked human plasma

In this article we report a novel method for colorimetric sensing and selective determination of a non-chromophoric drug-azithromycin, which lacks native absorbance in the UV–Visible region using unmodified silver nanoparticles (AgNPs). The citrate-capped AgNps dispersed in water afforded a bright yellow colour owing to the electrostatic repulsion between the particles due to the presence of negatively charged surface and showed surface plasmon resonance (SPR) band at 394 nm. Addition of positively charged azithromycin at a concentration as low as 0.2 μM induced rapid aggregation of AgNPs by neutralizing the negative charge on the particle surface. This phenomenon resulted in the colour change from bright yellow to purple which could be easily observed by the naked eye. This provided a simple platform for rapid determination of azithromycin based on colorimetric measurements. The factors affecting the colorimetric response like pH, volume of AgNPs suspension and incubation time were suitably optimized. The validated method was found to work efficiently in the established concentration range of 0.2–100.0 μM using two different calibration models. The selectivity of the method was also evaluated by analysis of nanoparticles-aggregation response upon addition of several anions, cations and some commonly prescribed antibiotics. The method was successfully applied for the analysis of azithromycin in pharmaceuticals and spiked human plasma samples with good accuracy and precision. The simplicity, efficiency and cost-effectiveness of the method hold tremendous potential for the analysis of such non-chromophoric pharmaceuticals.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide

Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
Authors
, , , ,