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Colorimetric sensing of palladium ions based on in situ generation of palladium nanoparticles as an activator for the thionine-hydrazine reaction

Pourreza, Nahid, Abdollahzadeh, Rezvan
Talanta 2019 v.196 pp. 211-216
absorbance, colorimetry, detection limit, hydrazine, ions, nanoparticles, pH, palladium, particle size, river water, soil sampling, spectroscopy, standard deviation, temperature, transmission electron microscopy, wastewater
In this article, a simple and rapid colorimetric sensing method was developed for the determination of palladium ions. The method is based on in situ generation of palladium nanoparticles (PdNPs) upon reduction by hydrazine which then acts as an activator on the reduction reaction of thionine by hydrazine. The formation of PdNPs was characterized by UV–Vis spectrophotometry, particle size analysis and TEM images. The reaction was followed by measuring the thionine absorbance at 599 nm with time. Several factors influencing analytical performance of the kinetic method such as concentration of reactants and electrolyte, pH of the sample solution and temperature were investigated to achieve the optimum conditions and highest sensitivity. This method showed a linear calibration curve in the concentration range of 8–1200 ng mL−1 for palladium ions. The limit of detection (LOD) was 6.5 ng mL−1 and the relative standard deviations were 3.8% and 1.3% (n = 8) for two palladium ion concentrations of 60 and 300 ng mL−1, respectively. The method was successfully applied to the determination of palladium in river water, pond water, wastewater and soil samples.