DEVELOPMENT OF AN ANALYTICAL METHOD FOR THE DETERMINATION OF LEAD BASED ON LOCAL SURFACE PLASMON RESONANCE OF SILVER NANOPARTICLES

Lead is environmental pollutant that even in low trace is harmful for human health and wildlife.In this study we presented a colorimetric method for determination of Pb 2+ in water by aggregation of silver nanoparticles capped citrate in the presence of deferoxamine as chelating agent.Silver nanoparticles were prepared by reduction of AgNO 3 with NaBH 4 .In the presence of Pb 2+ , mixture of silver nanoparticles capped citrate and deferoxamine aggregated and color of solution changed from light yellow to violet that depends on Pb 2+ concentration.As a result of aggregation, local surface plasmon resonance (LSPR) band of silver nanoparticles around 440 nm decreases and a new band appears at 580 nm that depend on Pb 2+ concentration.Under optimized conditions, linear relation of concentration of Pb 2+ and absorbance ratio (A 580 /A 440 ), was from 0.19 to 1.29 µmol L -1 and limit of detection of 0.056 µmol L -1 was found.Control experiments with the addition of 10 other metal ions (Ni 2+ , Cu 2+ , Ca 2+ , Al 3+ , Co 2+ , K + , Ba 2+ , Zn 2+ , Mg 2+ , Hg 2+ ) did not result in a distinct change in the color or in the absorption spectra.This approach was successfully tested for determination of Pb 2+ in well and tap water.