DTPA capped gold and silver nanofluids-facile synthesis and their application as chromium sensors

In the present study, we have explored the rapid green microwave synthesis of Diethylenetriaminepentaacetic acid (DTPA) capped Gold and Silver nanofluids. The formation of Au-DTPA and Ag-DTPA NPs were confirmed by surface plasmon resonance (SPR) peak observed around 520 nm and 400 nm for Au-DTPA NPs and Ag-DTPA NPs, respectively. The nanofluids were characterized by TEM, Raman spectroscopy and zeta potential analysis. The size of the nanoparticles in the nanofluids was observed to be of the order of 19-30 nm and 7-13 nm for AuNPs and AgNPs respectively. Raman analysis and SPR peak shift indicates sensing of Cr6+ and Cr3+. The Ag-DTPA NPs exhibited a linear concentration dependent response in the range 0.100-0.270 μM and 0.010-0.15 μM for Cr3+ and Cr6+ concentrations respectively while Au-DTPA NPs exhibited a linear concentration dependent response in the range 0.070-0.400 μM and 0.010-0.25 μM Cr3+ and Cr6+ concentrations respectively Limit of detection for Cr3+ and Cr6+ were found to be 0.05 μM and 0.005 μM respectively for Au-DTPA NPs while the detection limits were 0.05 μM for Cr3+ and 0.005 μM for Cr6+ in the case of Ag-DTPA NPs.