This material is based on the report by Hirashita and Uchiyama in Analytical Chemistry: “N. Hirashita and T. Uchiyama, BUNSEKI KAGAKU, 43, 757 (1994).”

Quantification of desorbed gases can be performed from the temperature-programmed desorption (TPD) spectrum measured using a TPD analyzer.

When the exhaust rate of the measurement chamber is sufficiently large compared to the pressure change in the chamber caused by the desorbed gases, the change in partial pressure of the desorbed gas components is proportional to the desorption rate (amount desorbed per unit time).

Since ion current and partial pressure are proportional in a mass spectrometer, the ion current ultimately becomes proportional to the desorption rate. Therefore, the total desorbed amount can be calculated from the area intensity obtained by integrating the ion current.
By determining the proportionality coefficient between area intensity and desorbed amount using a Si sample injected with a known amount of H+, the hydrogen desorbed amount can be determined from the m/z2 area intensity for various samples.
For molecules other than hydrogen, the proportionality coefficient can be calculated from parameters such as the ionization difficulty, fragmentation factor, and transmission rate of hydrogen and the target molecule.
Using this proportionality coefficient, quantification of molecules other than hydrogen is also possible.