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CTD48 H₂S probe

Measurement of sulphides and dissolved H₂S with amperometric micro-sensor

Monitoring of total dissolved sulphide concentrations (sum
of H2S, HS- and S2-) is one of the most important parameters for the analysis of natural standing water, wastewater and for oceanographic studies. Due to the high chemical reactivity of H2S and the rapid transfer of concentrations between liquid samples and the gas phase, measurement of dissolved hydrogen sulfide is difficult despite careful sampling.

The precise and reliable in situ measurement of this parameter is possible
with the CTD48 H2S probe for water up to 100 meters deep or with 10 bars of pressure. The integrated H2S micro sensor is the biggest innovation of this system, it allows fast measurement with very high resolution. The multiparameter probe continuously measures the concentration of dissolved hydrogen sulphide, taking into account the variations in temperature and pressure of the medium.

The CTD48 H2S probe can be connected to a power supply and a computer for on-line measurements, or be equipped with a battery module and memory for hard-to-reach environments and without a power supply.

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Measurement principle

The dissolved H2S passes through the gas permeable membrane. It diffuses to the working electrode where an electrochemical oxidation reaction takes place with the electrolyte adapted to the H2S. The current generated, proportional to the H2S concentration, is measured by the probe.
This current from 0 to 400 pico-amperes is then converted and used by the electronics of the probe to be compensated according to the temperature and the pressure measured.


  • Oceanographic, limnological and hydrological studies
  • Monitoring the quality of aquaculture ponds
  • Control of anti-H2S reagent injections for wastewater
  • Industrial process control


  • Continuous measurements, in situ without sampling
  • Automatic compensation for variations in pressure and temperature
  • Stand-alone version with battery and built-in memory
  • Micro H2S amperometric sensor, fast measurements, no interference with turbidity and low analyte consumption
Measuring principleamperometric
Measuring ranges- 10 μg / l ... 3 mg / l
- 50 μg / l ... 10 mg / l
- 500 μg / l ... 50 mg / l
Measuring principle (Pressure)full bridge piezo-resistive
Measuring principle (Temperature)Pt 100
Measuring principle (pH)combined pH electrode
Measuring principle (Pressure)0 ... 10 bars
Measuring ranges (Temperature)- 2 ... + 36°C
Measuring ranges (pH)0 ... 14 pH
Dimensions (L x d)diameter 48 mm, length 400 mm
Weight 1,1 kg
Interface (digital)RS232 serial / FSK-telemetry option
Data acquisitionSST-SDA software supplied (PC-Windows)
Power supply 9 ... 30 VDC
Consumption12 mA for 12 VDC
H2S micro sensor lifespan6 months in portable use, 10 months continuously (depends on the stress undergone by the variations in pH)
Calibration interval24 months
Warranty 24 months in the European Union
Temperature of the medium / sample0.1 ... + 30 ° C (40 ° C possible with specific calibration)
Ambient temperature0 ... + 40 °C
Storage temperature0 ... + 40 °C
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