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Shallow Water H₂S Probe

Measurement of dissolved H₂S concentrations

The H2S probe was developed for in situ measurement of changes in dissolved hydrogen sulfide concentrations in natural, industrial and wastewater.

Mounted on multiparameter systems such as CTD probes, this sensor is composed of a waterproof connector, a probe body incorporating an electronic signal transformation card and an H2S microsensor installed at the tip.

The amperometric measurement allows fine and fast measurements, approximately 2 seconds for 90% of the measurement even for concentrations of the order of a few micrograms, moreover the turbidity and the color of the water have no influence. on measure.

The sensor delivers an analog signal relating to the dissolved H2S concentrations. This “raw” output data must be integrated into a calculation formula supplied with the sensor, taking into account the temperature of the medium.


The sensor is designed to be integrated into industrial systems,
test benches, bioreactors, multiparameter systems equipped with a power supply and temperature measurement.

The H2S shallow water probe also allows the integration of a micro O2 sensor for dissolved oxygen measurements, replacing the micro H2S sensor.

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Measurement principle

The dissolved hydrogen sulphide passes through the gas permeable membrane. It diffuses to the working electrode where an electrochemical oxidation reaction takes place. The current generated, proportional to the partial pressure of dissolved H2S, is measured by the probe.
This current of 0 to 400 pico-amperes is then converted by the electronic card in the probe body into an analog signal of 0 to 3 VDC.


  • Monitoring and protection of wastewater networks
  • Control of anti-H₂S reagent injections
  • Industrial process control
  • Monitoring the quality of aquaculture ponds
  • Control of winemaking processes


  • Measurement without sampling directly in the medium
  • No interference with turbidity or water color
  • Maximum immersion depth 100 meters
  • Analog output signal without external controller
  • Waterproof SubConn connector
Measuring principleamperometric
Measuring ranges- type I: 0.05 ... 10 mg / l H₂S
- type II: 0.5 ... 50 mg / l H₂S
- type III: 0.01 ... 3 mg / l H₂S
- type SL: 0.003 ... 1.5 mg / l H₂S - Special Low
- type L: 0 ... 150 mg / l H₂S - Large
Measurement accuracy2% of the measured value
Response timeT90% 2 seconds
H₂ consumptionnegligible
Materialstitanium (probe body), silicone (membrane), glass (electrode), epoxy resin
Dimensions (d x L)24 mm x 235 mm
Power supply9 ... 30 VDC
ConsumptionNS. 0.5 mA at 12 VDC, approx. 0.25 mA for 24 VDC
Output signalanalog 0 ... 3 VDC
ConnectorsubConn BH-4-MP
H₂S micro sensor lifespan6 months in portable use, 10 months continuously (depends on stress by pH variations)
Interference on measurementno interference in salt water up to 40 g / l salt
Sensitivity to H2Scan lead to measurement errors and / or a reduction in the life of the micro sensor
Maintenancecleaning the measuring membrane with distilled water after each use
Temperature of the medium / sample0 ... + 30 ° C (40 ° C possible with a specific calibration on request)
Ambient temperature0 ... + 40 °C
Storage temperature0 ... + 40 °C
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