Dual-mode highly selective colorimetric and smartphone-based paper sensors utilizing silver nanoparticles for ultra-trace level omeprazole detection in complex matrices

Abstract

The present work focuses on the synthesis and optimization of highly stable, bare silver nanoparticles (AgNPs) as colorimetric sensor for trace-level detection of omeprazole. A novel approach combining AgNPs-based paper sensor and smartphone technology enables real-time analysis of omeprazole. The color change observed by the naked eye and shift in localized surface plasmon resonance (LSPR) were used to construct calibration curves. Both LSPR-based colorimetric sensing and paper-based sensing approaches were utilized for omeprazole detection in complex matrices. The limits of detection (LODs) were determined as 15 nM and 240 nM, with linear dynamic ranges of 0.05–40 µM and 0.1–50 µM, respectively. Recovery studies demonstrated % recoveries within the acceptable range of 90–110% and relative standard deviation (RSD) below 2%. Detailed characterizations including Fourier-Transform Infrared - (FTIR) Spectroscopy, Dynamic Light Scattering (DLS), zeta potential, Atomic Force Microscopy (AFM), and Field-Emission Scanning Electron Microscopy (FE-SEM) provided insights into sensing mechanism. This work offers a promising and practical solution for real-time omeprazole analysis with potential applications extending beyond pharmaceutical formulations. The developed colorimetric sensor based on AgNPs demonstrates high stability, sensitivity, and versatility, making it suitable for on-site and point-of-care omeprazole detection in various samples, including serum, plasma, urine, sea water, and tap water.