A green method for the simultaneous determination of Cd and Pb in soil and sediment by slurry sampling graphite furnace atomic absorption spectrometry

Abstract

A simple and reliable green method for the simultaneous determination of Cd and Pb in soil and sediment by slurry sampling graphite furnace atomic absorption spectrometry (SlS-SIMAAS) is proposed. Under the optimum conditions, sample masses in the range of 5–40 mg were weighed into polypropylene tubes (50 mL) and diluted (30–50 mL) with 0.1% (v/v) of nitric acid + 0.025% (m/v) of Triton^® X-100. Considering the compromised conditions, the heating program for the simultaneous determination of Cd and Pb used 600 °C and 2000 °C as pyrolysis and atomization temperatures, respectively. Several chemical modifiers were investigated, but the best recovery and reliable result were obtained using the universal mixture 5 μg Pd + 3 μg Mg. A volume of 10 μL of slurry was introduced into the graphite tube after manual homogenization. The detection limits (n = 10, 3σ) were 0.14 μg L⁻¹ (1.4 pg) for Cd and 1.2 μg L⁻¹ (12 pg) for Pb. The characteristic masses were 1.2 pg and 25 pg for Cd and Pb respectively. The reliability of the proposed method was checked using Certified Reference Materials (Buffalo River, IEAEA 356, MESS 1, BCSS1 and NIST 2703) analysis.