Inductively Heated Vaporizer for Inductively Coupled Plasma Mass Spectrometry

Abstract

An inductively heated vaporizer (IHV) was used to introduce analyte, as a dry aerosol, into an ICP-MS instrument. Sample volumes of 5–300 µl were pipetted into a graphite cup, which was then placed in the induction coil of the IHV to dry, pyrolyze and vaporize the analytes of interest. A small amount of N₂, added to the Ar carrier flow, was used to prevent arcing between the graphite cup and the induction coil of the induction furnace. Experimental parameters such as Ar carrier flow, rf power and torch position were optimized by placing a small crystal of I₂ in the graphite cup of the IHV and maximizing the¹²⁷I⁺signal. Linearity of the calibration graphs improved and integrated signal intensity increased with increased mass of analyte deposited in the graphite cup. Limits of detection (LODs) in the range 3–100 pg ml^–1were achieved for Ag, Pb, Cd, Tl and Zn. When compared with solution nebulization, these LODs represent an improvement of 3- to 30-fold depending on the element.