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OnlineH2S - Hydrogen sulphide in gases

Continuous quantitative determination of hydrogen sulphide (H2S) in gas mixtures

Analyzer for online determination
of H2S in gases

The OnlineH2S is used for the continuous quantitative determination of hydrogen sulphide (H2S) in gas mixtures.

The system is designed with an integrated dilution step for measurement of very high concentrations (100 - 20000 ppm). Also very low contents in the range of odour treshold (0.1 - 100 ppm) can be measured.

The OnlineH2S contains a selective amperometric sensor with gas selective membranes, membrane pumps for gas transportation and sample transfer and an integrated PC for continuous recording of measurement data, trends and alarm states. The measurement values can be transmitted via digital (alarm-) and analog outputs into the control room.

Due to an integrated cleaning system the gas analysis in O2 free gases (e. g. biogas) is realized without any drift effects. Because of the stress free mode of operation, the sensor lifetime is considerable increased.

The operation principle makes the OnlineH2S ideal as a basis for H2S adjusted regulation of enrichment and cleaning steps.

The instrument is available in the same design for monitoring of ammonia gas (NH3), sulfur dioxide (SO2) or ozone (O3).


  • Online determination of the current H2S concentration as basis for adjusted regulations (e. g. pump sump, gravity pipeline, collecting tank)
  • Processes of anaerobic digestion, fermentation processes
  • Environmental analytics
  • Wastewater analysis
  • Monitoring of landfill leachate

Fields of applications:

  • Municipal association for sewage treatment
  • Industrial sectors
  • Biogas plants
  • Petroleum processing


  • Continuous H2S determination in gases (measurement duration < 5 min)
  • Robust method of analysis
  • Automatic sample dosing
  • Easy calibration steps
  • Selective electrochemical sensor with no cross-sensitivity
  • Software easy-to-use
  • Output value of H2S as a 4 - 20 mA signal for integration into the local control system
  • Long lifetime of the sensors due to the intermittent gas switching
  • Integrated rinsing steps for measuring of continually fresh samples
  • Active sample intake of the gas up to a distance of 100 m – variable setup of device (wall mounted)
  • Also available for determination of ammonia gas (NH3), sulphur dioxide (SO2) or ozone (O3)

Data sheet




ECH Elektrochemie Halle GmbH
Otto-Eißfeldt-Straße 8
06120 Halle (Saale)

Tel.: +49 345 279570-0
Fax: +49 345 279570-99
Mail: info@ech.de

Sales and Service Center UK

ECH Scientific Limited
Building 69, Wrest Park, Silsoe
Bedfordshire, MK45 4HS
United Kingdom

Tel.: +44 1525 404747
Fax: +44 1525 404848
Mail: info@ech.de