Utilizing modified gold nanoparticles as a colorimetric probe for selective determination of three triptan-family drugs

Gold nanoparticles (AuNPs) are considered highly stable metal nanoparticles flaunting several outstanding features including facile synthesis and surface modification, excellent biocompatibility and strong Surface Plasmon Resonance (SPR) in the visible region of the spectrum which make them the ideal candidate for naked-eye detection of analytes [1,2].Drug abuse is a major issue associated with a myriad of medical, social, and legal problems. To date, most of the analytical techniques employed for the determination of opioids and their metabolites in biological samples have involved the application of sophisticated and costly equipments such as GC–MS, HPLC, capillary and electrochemical analysis [3-5]. In this work, we demonstrated the use of 4-Amino-5-(2-hydroxyphenyl)-1,2,4-triazole-3-thione (AHTT) -capped AuNPs as a facile colorimetric probe for selective determination of triptan-family drugs (Rizatriptan, Naratriptan and Sumatriptan). The absorption spectra and solution color of AHTT-AuNPs undergo dramatic changes on exposure to three analytes with new surface plasmon resonance (SPR) peaks appearing at 610, 600 and 594 nm for Rizatriptan, Naratriptan and Sumatriptan, and concomitant color change from red to blue. This is assumed to result from the aggregation of AHTT-AuNPs induced by three triptan-family drugs. The UV–visible absorption spectra, FT-IR, and TEM techniques were used to confirm the aggregation of AHTT-AuNPs by three triptan-family drugs. Under the optimized conditions, good linear relationships (R2 = 0.986–0.999) were obtained in the range of 1-100 µM, with limit of detections in the range of 0.2–3.24 µM for the three triptan drugs. This method was successfully applied to detect the triptan-family drugs simultaneously in pharmaceutical and human blood serum samples.