One-pot synthesis of gold nanoparticles by using 4-aminoantipyrine as a novel reducing and capping agent for simultaneous colorimetric sensing of four triptan-family drugs

We report the use of 4-aminoantipyrine (AAP) as a novel reducing and capping reagent for the one-step synthesis of gold nanoparticles (AuNPs) and their colorimetric sensing application for the analysis of four triptan-family drugs (naratriptan, sumatriptan, rizatriptan and zolmitriptan) in pharmaceutical samples. Parameters such as reagent concentration, temperature and reaction time were studied for the synthesis of AAP-AuNPs. The synthesized AAP-AuNPs were characterized by using UV-visible spectrometry, dynamic light scattering (DLS) and transmission electron microscopy (TEM) techniques. AAP is used to reduce Au3+ and to provide large conjugate network on the surfaces of AuNPs which allows them to act as a probe for the colorimetric sensing of triptan-family drugs. The newly synthesized AAP-AuNPs are pink in color due to the intense surface plasmon resonance (SPR) band at 544 nm. On the addition of triptan-family drugs, the pink color of AAP-AuNP solutions turns blue with an accompanying dramatic SPR band red-shift from 544 to 773, 667, 725 and 745 nm for naratriptan, sumatriptan, rizatriptan and zolmitriptan, respectively. It is presumed that the color change is a result of AAP-AuNP aggregation induced by triptan-family drugs. The color change is used for both observation with the naked eye and the colorimetric determination of four triptan-family drugs in pharmaceutical formulations.