Technical Specifications

H2S MEDOR - Hydrogene sulfide
  • Detection limits:
    • H2S/TOS TS MEDOR® ppb: 5 ppb H2S (7 μg/m3)
    • H2S/TOS TS MEDOR® ppm: 0.1 ppm H2S (0.1417 mg/m3)
  • Detection range: H2S / TOS / TS
    • 0/10, 0/100 or 0/1000 (ppb or ppm)
    • Low % with HC sampling valve
  • Relative Standard Deviation:
    • RSD < 3% on concentration over 48H.
    • RSD < 0.6% on retention time over 48H.
  • Results:
    • Hardware storage
    • MODBUS communication protocol (optional)
    • 4-20mA (optional)
  • Linearity:
    • 0.995 for all compounds
  • Cycle time:
    • H2S / TS result in 2 min for 0-3 ppm range
    • H2S / TS result in 5 min for higher range
  • Gas supply:
    • Carrier: Dry air or N2 (3 bars): 5 ml/min.
    • CALIB: in continuous 50 ml/min. (option)
    • CALIB during validation ~ 250ml/min (option)
    • Pneumatic valve 90ml/commutation

H2S, total organic sulfur and total sulfur

The H2S/TOS TS MEDOR® is an autoGC-ED (MEDOR® Electrochemical wet cell Detector) for the analysis and monitoring of H2S, TOS and TS.

  • Different configurations exist depending on the application and concentration range : HS2/TOS TS MEDOR ppb for 0-1 ppm and H2S/TOS TS MEDOR ppm for 0-10 / 0-50 / 0-100 ppm


  • Automatic sampling using a loop
  • Automatic loop injection on metallic capillary column
  • Isothermal gas chromatograph
  • Detection of all compounds eluting from the column performed by MEDOR® detector : Electrochemical wet cell Detector which is a Sulfur Specific Detector (SSD)
  • Signal provided by electrochemical reaction between the wet cell electrolyte and the sulfur compounds
  • Fully compliant with ASTM D 7493-14 : Standard Test Method for On-line Measurement of Sulfur Compounds in Natural Gas and Gaseous Fuelsby Gas Chromatograph and Electrochemical Detection.
  • Compliant with ASTM D 5504-20 : Standard Test Method for Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatography and Chemiluminescence with alternative detector.

Key points

  • Continuous monitoring with automatic online sampling
  • Analytical performances :
    – Specific, linear and very sensitive to sulfur compounds
    – Results validation by automatic standard injection
    – Long term stability using detector installed in reservoir
  • Extremely low maintenance :
    – Very long life time detector with electrolyte, up to 10 years.
    – Low gas consumption, can be reduced in option
    – More than 10 years data storage
    – No cylinders required thanks to internal calibration tube and gas generators
  • Automatic control with process device
  • Intelligents system with tunable and interactive alarm levels
  • Powerful VISTACHROM Chromatotec® software :
    – Remote monitoring & injection control
    – Full traceability with on board archiving of results and chromatograms

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