4. Conclusion

Hydrogen measurement, the measurement of traces of an element that doesn't want to remain in the metal but is found everywhere in nature as a potential pollutant, is not an easy task. It is imperative to master the various stages of the analysis: sample collection and preservation (criterion of representativeness), preparation, extraction and actual measurement of the hydrogen (criterion of accuracy and function of the type of hydrogen sought).

In most cases, hydrogen is extracted by raising the temperature, either by remaining in the solid state or by melting the sample:

• pressure measurement (Mac Leod gauge) ;

• thermal conductivity measurement (catharometer) ;

• measurement by mass spectrometry, gas chromatography...

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