EVALUATION OF A MODIFIED COMMERCIAL GRAPHITE-FURNACE FOR REDUCTION OF ISOBARIC INTERFERENCES IN ARGON INDUCTIVELY COUPLED PLASMA MASS-SPECTROMETRY

A modified Perkin-Elmer HGA 300 graphite furnace has been investigated for sample introduction into inductively coupled plasma mass spectrometry (ICP-MS). Its application for the reduction of matrix related isobaric interferences at m/z 56 (ArO+ and the major isotope of Fe) and m/z 75 (ArCl+ and monoisotopic As) was studied. Optimization of operating conditions for the ETV instrument, including carrier flow, drying temperature and coolant flow, was performed. Absolute detection limits were found to be 1.5 pg for As and 0.2 pg for Fe, with reproducibility between 5 and 8% RSD for ten 10-mu-l sample injections of 10 ng g-1 Fe and As. Linear responses were found to be three orders of magnitude for Fe and four orders of magnitude for As.