Rapid detection of Cr(VI) by AgNPs probe produced by Anacardium occidentale fresh leaf extracts

Abstract

Nowadays necessities for the green synthesis of nanoparticles are enlarged because of its neutral toxicity and eco-friendly advantages. In this present study, we have explored the rapid biosynthesis of AgNPs at room temperature by the fresh leaf aqueous extract of Anacardium occidentale. Aqueous extracts were prepared at different temperatures 60, 80 and 100 °C. Formation of silver nanoparticles (AgNPs) was confirmed by surface plasmon resonance (SPR) peak observed around 400–420 nm in UV–Visible spectra. Among the extracts prepared, 80 °C extract showed good shift in UV–Visible spectrum during Cr(VI) detection and a good linear relationship was found between the absorbance ratio (A510/A400) against 100 mM–1 μM concentration of Cr(VI). Cr(VI) was confirmed by the red shift of SPR position from 400 to 510 nm. Detection limit of our prepared probe is 1 μM and this simple technique exhibiting high selectivity to Cr(VI) over other tested heavy metal ions. Finally, efficient 80 °C extract synthesized AgNPs were characterized by XRD, SEM and TEM. XRD characterization confirmed its face centered cubic structure and confirmed that the prepared AgNPs are crystalline in nature. TEM and SEM characterization results revealed that the AgNPs are in spherical nature. The size of AgNPs was found to be 40–60 nm.