Abstract
A study was made of the possible mechanism of tellurium atomization with the use of palladium and palladium–magnesium nitrate as chemical modifiers in electrothermal atomic absorption spectrometry (ETAAS). The experiments were performed by adding various masses of Pd and Pd–Mg(NO3)2 to the standard solution of tellurium and then injecting them into an ETAAS for the determination of tellurium. Absorbance profiles of Te peaks were found to be sensitive to the mass of Pd present. Slightly positive shifts in the temperature of peak appearance were observed, while a higher level of Pd caused increasing shifts in the peak appearance temperature and a significant tailing. However, these phenomena can be avoided by adding a large amount of Mg(NO3)2. The effect of various amounts of modifiers on the analytical signal of tellurium was also investigated by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) for monitoring the analyte behavior through a heating cycle from 120 to 2650 °C. The positive shift in the peak appearance temperature was also observed on increasing the mass of Pd. Several marked signal pulses at temperatures between 1500 and 2650 °C were observed and assumed to result from the different migration rate of tellurium out of the droplets of Pd and the desorption of the vapor condensation for [Te, Pd] coupling. The typical distribution of Te and Pd onto the surface of the graphite tube after the atomization step was also investigated by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and scanning electron microscopy (SEM).