Behzad Aibaghi-Esfahani

The application of sulfur nanoparticles as an efficient adsorbent for the solid-phase extraction and determination of the trace amounts of Pb and Pd ions was investigated in environmental samples using flame atomic absorption spectrometry. Effects of various parameters such as pH, flow rate of sample and eluent, type and concentration of eluent, sample volume, amount of adsorbent and interfering ions were investigated and optimized. The results showed that the optimal conditions for quantitative recovery of the metal ions by adsorption and elution on the sulfur nanoparticles were achieved by employing a flow rate of 2 ml min-1, a pH of 9.5 for the sample solutions, and an eluent composed of 4.0 M HNO3 in ethanol. The maximum adsorption capacity of SNPs as sorbents at optimum conditions for lead and palladium ions was found to be 2.80 mg g-1 and 2.87 mg g-1, respectively. At optimum conditions, the detection limits of this method were 0.3 and 2.5 ng ml-1 for Pb(II) and Pd(II), respectively. The proposed procedure was applied to the determination of the metal ions in soil and water samples.

A sensitive and simple solid-phase preconcentration procedure for the determination of trace amount of lead by flame atomic absorption spectrometry (FAAS) is developed. The method is based on the adsorption of Pb2+ on the column of fine grinded eucalyptus stem adsorbent, elution of the column by nitric acid and subsequent determination by FAAS. The effect of different variables such as pH, eluent type, flow rate and interfering ions on the recovery of the analyte was investigated and optimum conditions were established. The adsorption of lead onto fine grinded eucalyptus stem can formally be described by a Langmuir equation with a maximum adsorption capacity of 4.49 mg g-1. A preconcentration factor of 50 was achieved using the optimum conditions. The calibration graph was linear in the range 10-125 ng mL-1 of lead in the initial solution with r = 0.9982. The limit of detection based on 3Sb criterion was 4.5 ng mL-1 and the relative standard deviation for eight replicate measurements of 30 and 80 ng mL-1 of iron was 3.6 and 2.8%, respectively. The method was successfully applied to the determination of lead added to well, tap and wastewater samples.