Use of Palladium and Iridium as Modifiers in the Determination of Arsenic and Anitmony by Electrothermal Vaporization Inductively Coupled Plasma Mass Spectrometry, FollowingIn Situ Trapping of the Hydrides

Abstract

A study was made of Pd and Ir as modifiers in the determination of As and Sb by electrothermal vaporization inductively coupled plasma mass spectrometry, following hydride generation andin situ trapping of the hydrides in the graphite furnace (HG-ETV-ICP-MS). The trapping temperature was 300 °C and the vaporization temperature 2300 °C. The signal intensities of As and Sb were found to increase with decreasing volume and concentration of the Pd modifier solution; therefore, a low volume (10–20 µl) and concentration (10–20 mg l^–1) of modifier seems advisable. The observed effects were probably due to changes in the transport of analyte to the plasma, because the same effects were not observed when the trapped hydrides were determined by electrothermal atomic absorption spectrometry. It is also shown that Ir can be used as a modifier in HG-ETV-ICP-MS; Ir and Pd are about equally efficient for this purpose. The advantages of using Ir as modifier are discussed.