Method of using an aerosol to calibrate spectrometers
AssigneeAir Products and Chemicals, Inc.
InventorSuhas Narayan Ketkar
Life of this patent
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Abstract
Using a nebulizer gas, sub micron and micron size particulates can be generated from a solution containing salts covering a broad range of elements. The fractional concentration of elements can be determined by bubbling the aerosol through aqueous acid and analyzing the aqueous acid for metals. The nebulizer can be coupled to an ICP (Inductively Coupled Plasma) torch and the ICPMS (Inductively Coupled Plasma Mass Spectrometer) or ICPOES (Inductively Coupled Plasma Optical Emission Spectrometer) response to different elements can be determined. This provides the response factor of the ICPMS or ICPOES for different elements.
Claims19
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.
A system for use in calibrating an inductively-coupled plasma (ICP) spectrometer to analyze metallic impurities in gases, said system comprising:
- at least three different aqueous standards;
- a nebulizer for nebulizing each one of said at least three different aqueous standards in series with a sample gas having unknown metallic impurities therein to form an aerosol, said nebulizer having a known efficiency;
- an ICP spectrometer for receiving and analyzing the intensities of metallic impurities in said aerosol to generate data regarding intensities of metallic impurities;
- and
- means for deriving a linear relationship between intensity and concentration for each of said metallic impurities based upon said data, said linear relationship defining a slope and an intensity intercept, said deriving means also determining the concentration of metallic impurities in the sample gas from the absolute value of said intensity intercept divided by said slope for each of said linear relationships, and wherein said deriving means takes into account said known efficiency of said nebulizer.
A system for use in calibrating an inductively-coupled plasma (ICP) spectrometer to analyze metallic impurities in gases, said system comprising:
- at least three different aqueous standards;
- a nebulizer for nebulizing each one of said at least three different aqueous standards in series with a sample gas having unknown metallic impurities therein to form a wet aerosol;
- a desolvator, coupled to said nebulizer, for converting said wet aerosol into a dry aerosol and wherein said nebulizer and desolvator have a known efficiency;
- an ICP spectrometer for receiving and analyzing the intensities of metallic impurities in said dry aerosol to generate data regarding intensities of metallic impurities;
- and
- means for deriving a linear relationship between intensity and concentration for each of said metallic impurities based upon said data, said linear relationship defining a slope and an intensity intercept, said deriving means also determining the concentration of metallic impurities in the sample gas from the absolute value of said intensity intercept divided by said slope for each of said linear relationships, and wherein said deriving means takes into account said known efficiency of said nebulizer and desolvator.
Dependencies are inferred from the claim text.