Electron Impact - Mass Spectrometer



The PEMSense is an electron impact mass spectrometer (EI-MS) for the fast measurement of H2, N2, O2, H2O and CO2 on PEM fuel cells.

The analyzer is equipeed with a dual sample gas inlet, a low flow inlet (< 60 ml/min) for the anode and a standard flow inlet for the cathode and exhaust.


Functional Diagram


Typical Applications

  • Fuel cell testing
  • Fuel cell development

Measureable Compounds (excerpt)

Permanent gases

Substance name Molecular formula
Hydrogen H2
Oxygen O2
Nitrogen N2


Substance name Molecular formula
Water H2O

Rare gases

Substance name Molecular formula
Argon Ar


Substance name Molecular formula
Methane CH4


Technical Data EI-MS Technical Data EI-MS
Mass range 1 – 100 amu Ambient temperature 20°C – 35°C
Resolution < 1 amu Humidity max. 80% (non-condensing)
Analysis time >= 10 msec/amu Gas consumption cathode 3000 ml/min
Measuring range 100 ppm – 100 Vol% Gas consumption anode 3 - 60 ml/min
Response time cathode T90 < 100 msec Gas inlet temperature 50°C – 180°C adjustable
Response time anode T90 < 1 sec Gas inlet pressure cathode 1 – 2 bar(a)
Lower detection limit <= 100 ppm Gas inlet pressure anode 0.75 – 6 bar(a)
Concentration drift <± 5% over 24h Power 230V/50Hz or 115V/60Hz 800W
Reproducibility <± 3% Dimensions (W x H x D) 534 x 743 x 639 mm
Accuracy <± 3% Weigth 62 kg

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