Patent ID: 6686999
Filing Date: 2004-02-03
Classification: G01N

Abstract:
A method for calibrating an inductively-coupled plasma (ICP) spectrometer to analyze metallic impurities in gases, said method comprising the steps of:(a) providing a sample gas having unknown metallic impurities therein; (b) nebulizing the sample gas with a first aqueous standard containing no metallic impurities into an aerosol, said nebulizing comprising a known efficiency; (c) inputting and analyzing said aerosol in the ICP spectrometer to measure intensities of metallic impurities therein, said analyzing comprising the application of said known efficiency to said measured intensities to form a first set of metallic impurities data; (d) conducting a standard addition process utilizing different aqueous standards of increasing concentrations of metallic impurities therein that are nebulized with the sample gas and analyzed in said ICP spectrometer to obtain a plurality of sets of data for each of said metallic impurities and to which said known efficiency is applied; (e) deriving a relationship between measured intensity and concentration for each of said metallic impurities based upon said plurality of sets of data and said first set of metallic impurities data, said relationship defining a slope and a measured intensity intercept; and (f) determining the concentration of metallic impurities in the sample gas from the absolute value of said measured intensity intercept divided by said slope for each of said linear relationships.