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.