A b s t r a c t
Arapid and simple procedure was developed for selective and sensitive determination of ultra-trace silver in biological and environmental samples using the electrodeposition on a graphite probe modified with palladium followed by electrothermal atomic absorption spectrometry. Several experimental parameters for the electrodeposition, such as deposition potential, electrolyte concentration, pH of solution and deposition time were optimized. The calibration graph after preconcentration was linear in the range of 10-250 ngL–1 with correlation coefficient of 0.9989 under the optimum conditions for procedure. The limits of detection (LOD) and quantification (LOQ) base on (3σ) and (10σ) were 2.8 ngL–1 and 9.4 ngL–1 respectively. Related standard deviation (RSD) for eight replicatemeasurements of 100 ngL–1 silver was 4.3%. Samples were digested completely in a closed microwave digestion system using only perchloric acid, and interference owing to various cations was also investigated. The proposed procedure was successfully applied to determine silver in blood, urine and some environmental samples with satisfactory analytical results.
Reza Moradkhani, Ahmad Rouhollahi, Hamid Shirkhanloo and Jahan Ghasemi
Results presented in this work demonstrate an effective approach to improve the detection limit of ETAAS for silver determination. This procedure is very selective and shows high tolerance to interferences from complex matrix due to electrodeposition step. Also, the proposed method is easy, safe, rapid and inexpensive for preconcentration and separation of ultra-trace silver and determination by ETAAS in environmental and biological samples.