Utility of cloud-point preconcentration and spectrophotometry for determination of trace amounts of palladium(II) and their analytical applications

A cloud-point preconcentration process using micelle of the cationic surfactant cetyltrimethylammonium bromide to extract Pd(II) from aqueous solutions was investigated. The method is based on the color reaction of palladium with 4-(2-benzothiazolylazo)2,2′-biphenyldiol in the presence of potassium chloride at pH 3.85 phosphate buffer media and micelle-mediated extraction of complex. The optimal extraction and reaction conditions (e.g., reagent concentration, surfactant concentration, and the effect of time and temperature) were studied and the analytical characteristics of the method (e.g., detection and quantification limits, linear range, preconcentration and improvement factors) were obtained. Linearity was obeyed in the range of 2.0-240 ng mL−1 of Pd(II) ion and the detection limit of the method was 0.6 ng mL−1. The relative standard deviation (RSD) and relative error for six replicate measurements of 150 ng mL−1 Pd(II) were 1.05% and 1.36%, respectively. The interference effect of anions and cations was also tested. The method was applied to the determination of Pd(II) in water, spiked water, synthetic alloys and in Pd-charcoal, plating effluents, catalyst and soil samples.