Instrumental Gas Analysis (IGA)

Take Home Point:

H, C, O, N and S bulk analysis   

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What It Provides:

Provides concentration tables of H, C, O, N and S 

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Brief Description:

 

Heat In/Gases Out

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In IGA samples are heated releasing characteristic gases for H, C, O, N and S that are then measured via IR Absorption or Thermal Conductivity.  

 

C and S are analyzed by Combustion Analysis.  Samples are first preweighed in a ceramic crucible/boat.  The sample/crucible is then placed in a high temp induction furnace flooded with high purity O2.  Carbon is converted to CO and CO2 and a heated catalyst converts the former to CO2.  S is converted to SO2.  The total CO2 and SO2 formed during the process is measured by IR absorption allowing the total C and S to be calculated.  

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N, O and H are measured using Inert Gas Fusion.  Samples are first preweighed and then placed in a graphite crucible.  The sample/crucible is placed in an impulse furnace and rapidly heated to extremely high temperature (2000-3000C) resulting in the sample fusing to a molten state.  H2 and N2 gases dissociate from the molten material while O present within the sample reacts with the graphite crucible forming CO and CO2.  The CO and CO2 are measured via an IR detector.  The gas then flows through a heated reagent to oxidize the CO into CO2 and the H2 into H2O.  CO2 and H2O are then detected in another set of IR cells.  Both species are then removed via a scrubber allowing N2 to be subsequently analyzed with a thermal conductivity detector.  This set of measurements allow O, H and N concentrations to be calculated based on calibration standards.  Note that some manufacturers may utilize slightly different processes for O, H and N measurements.      

What is Detected:

H, C, O, N and S

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Detection Limits:

~0.1ppm

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Information Depth:

Not Applicable

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Applications:

1. Determination of H, C, S, N and O in solids (e.g. metals, alloys)

2. Determination of H, C, S, N and O in powders/particulates (e.g. ceramic powders).

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Manufacturers:

1. ELTRA Elemantal Analyzers

2. LECO