Hedysarum polysaccharides mediated green synthesis of gold nanoparticles and study of its characteristic, analytical merit, catalytic activity

We reported an eco-friendly, rapid and easy method for the green synthesis of gold nanoparticles (AuNPs) using Hedysarum polysaccharides (HPS) extracted from Radix Hedysari. To deeply explore the synthetic mechanism, the monosaccharides that made up HPS and other Radix Hedysari extract were also used as reductant to synthesize AuNPs. A series of techniques were conducted to confirm the formation of HPS-AuNPs. Moreover, as a sensitive optical detector, the large-sized HPS-AuNPs was used to selectively detect iron ion (Fe³⁺) among the other metal irons and was successfully applied in the tap water detection with a wide range of 1 μM to 10 mM, a low detection limit of 0.57 μM. Besides, the catalytic activity of HPS-AuNPs was also proved to be well in the reduction of 4-nitrophenol to 4-aminophenol by NaBH₄. This is the first report for the green synthesis of HPS-AuNPs, providing a sensitive detector and a well-active catalyst.