In-Situ Separation and Determination of Palladium from Platinum Based on Different Vaporization Temperatures by Electrothermal Vaporization Inductively Coupled Plasma Optical Emission Spectrometry with YPA4 Resin Acting Both as Adsorption Material and Chemical Modifier

摘要

A new method has been developed for in-situ separation of Pd from a Pt matrix and determination of trace Pd based on different vaporization temperatures by electrothermal vaporization (ETV) inductively coupled plasma optical emission spectrometry (ICP-OES) with the use of polythioether backbone modified with a diaminoisopropylmercaptane chelating group (YPA4), both as solid phase extractant and chemical modifier. In 0.5 M HNO3, Pd and Pt can be adsorbed by YPA4. The resin loaded with Pd and Pt was then prepared to form a slurry that can be directly introduced into the graphite furnace without any pretreatment. The factors affecting in-situ separation of Pd from the Pt matrix were investigated in detail. It was found that, in the presence of YPA4, Pd could be quantitatively vaporized at lower vaporization temperatures (1800 °C–1900 °C), while Pt could not be vaporized from the graphite furnace at the same temperature, its quantitative vaporization temperature being 2600 °C. Based on the different vaporization temperatures, in-situ separation of Pd from the Pt matrix and determination of trace Pd by ETV-ICP-OES was achieved in the temperature range of 1800 °C–1900 °C. Under the optimized conditions, the detection limit (3σ) of Pd is 60 pg, and the relative standard deviation (RSD) is 5.6% (n=9, C=0.2 µg mL−1). The method has been applied to the determination of trace Pd in anode slime and Auto Catalyst NIST SRM 2557 reference material, and the determined values coincide with the certified values.