The S-Online for online determination of sulfides provides the opportunity to measure sulfides/H2S even below the odor threshold in wastewater. By the combination of a highly efficient gas extraction and a selective detection method, sulfide/H2S is determined in aqueous solutions.

After dosing, the sample is acidified forming H2S gas which is then degassed from the solution in the H2S analyzer. The gas is then carried into an amperometric sensor that is sensitive to detecting H2S.

The gas is then carried into an amperometric sensor that is sensitive to detecting H2S. Therefore, interferences of the sample matrix do not affect the sensitive measurement. Even complex matrices such as industrial wastewater (e. g. containing alkaline wastewater, hydrocarbons or ammonia) can be monitored instantly as well as providing reproducible results.

The wastewater sample is taken up automatically. By the use of an integrated automatic back-purging, the system is robust and low-maintenance.

The measuring range can be varied widely and can also be adjusted to the required application. For instance, the S-Online can be used as a H2S dependent controlling system for chemical wastewater treatment. The results can be transferred through digital alarm- and analog outputs into the measuring station.

Average measuring time: 5 … 15 minutes (dependent on the sample)
Range: 0.01 … 1000 ppm
Resolution: 0.1 µg abs., output signal linear
Sample volume: 0.01…20 mL
Gas supply: internal pump or compressed air
Gas flow: up to 50 L/h
Operating voltage: 220 – 230 V, 50 Hz, 2 A
Power consumption: 100 W
Type of protection: IP54
Weight of the analyzer: 20 kg
Dimensions of the analyzer: 600 x 720 x 370 mm (W x L x H)


  • Complete extraction of H2S from aqueous samples
  • No cross sensitivity (realized by indirect method)
  • Easy-to-use calibration
  • Completely automatic sample dosing
  • Simple and well-arranged software
  • Robust and fast method fo analysis (up to 12 analyses per hour)
  • Output 4 - 20 mA for the integration of the H2S signal in the local system
  • High durability of the sensor by intermittent gas circuit
  • Integrated rinsing steps to ensure a constant analysis of a present sample