Measurement of dissolved sulphides and H₂S
The determination of dissolved hydrogen sulphide and total dissolved sulphide concentrations is necessary for the control of injection of H2S reagents into sewerage networks, industrial process control, moni- toring of aquaculture ponds and processes. of vinification. Due to its high chemical reactivity and rapid transfer of concentrations between liquid samples and the gas phase, the measurement of dissolved H2S is difficult despite careful sampling.
Accurate and reliable in-situ determination of concentrations is now possible with the MS08-H2S for online or portable measurements. The integrated H2S micro sensor is the biggest innovation of this system, it allows a fast measurement with a very high local resolution. The multi-parameter MS08 system collects raw H2S data and temperature information to perform compensation calculations and display dissol- ved H2S concentration in mg/l.
Thanks to the parallel measurement of the pH, the system is able to calculate the total dissolved sulphide concentrations in mg/l.
Dissolved H2S and TDSA measurement can be done with two probes type:
- The MS08 device, for portable or laboratory measurement: this kit contains a reading data box and two probes are linked to it. The titanium probe contains the H2S amperometric micro-sensor and the other probe combine a pH sensor and a temperature measurement, necessary for the concentration determination. The MS08-H2S is designed for portable measurements (about 12 hours of battery life) and can also be connected to a 220 VAC power supply for continuous measurements.
- The CTD48 system, stronger, for a continuous use in water: the probe contains in the head several sensors that allow concentration calculation. The titanium protection cage includes then a H2S amperometric micro-sensor, a pH sensor, a temperature sensor and can also hold a pressure sensor. Measurement data are operated through electronic embedded in the probe’s body. A CTD48M version that records data is also available.
The dissolved H2S passes through the gas permeable membrane. It diffuses to the working electrode where an electrochemical oxidation reaction takes place. The generated current, proportional to the hydrogen sulphide concentration, is measured by the probe.
This current, 0 to 400 picoamperes, is converted and operated by the MS08, the measurement data are compensated with temperature measurement and pH.
- Monitoring and protection of wastewater networks
- Control of H2S reagent injections
- industrial process control
- Aquaculture tanks monitoring
- Controle of winemaking processes
- Immersed measurement without sampling
- No interference with thurbidity
- Automatic temperature and pH compensation
- Portable / laboratory and continuous measurements
- Data display, H2S, total sulphide, T° and pH
- Extracting data to computier via USB
|Measurement principle||Amperometric measurement with T° and pH compensation|
|Measurement ranges||- type I 0,05 µg/l … 10 mg/l H₂S|
- type II 0,5 µg/l … 50 mg/l H₂S
- type III 0,01 µg/l … 3 mg/l H₂S
- type SL 0,003 µg/l ... 1,5 mg/l H₂S
- type L 0 µg/l ... 150 mg/l H₂S
|Response time||T 90% 2 seconds|
|Accuracy||2% of the measured value|
|Additionnal sensors||temperature and pH, combined|
|Interferences on measurement||no interference in salt water up to 40 g/l of salt|
no interference in presence of: carbon dioxide (up to 25.38 vol.%), Methane (up to 5.78 vol.%), Hydrogen (up to 0.544 vol.%), Ammonia (up to at 1000 ppm (v)), carbon monoxide (up to 92 ppm (v)), CS2 (up to 5 vol%), organic solvents (up to 20% vol.), acetic acid (up to at 1 mol / l), dimethyl sulfide
|Micro-sensor H2S lifetime||6 months in portable use, 10 in continuous (depends on stress by pH variations)|
|Power supply||6 batteries Mignon / 220 VAC, charger supplied|
|Housing material||H2S probe - titanium / temperature-pH sensor - plastic|
|Dimensions (d x L)||H2S probe - 17 mm x 205 mm / temperature-pH - 12 mm x 120 mm|
|Interface||data display on integrated screen - H2S / T° / residual current / pH / Total dissolved sulphide|
RS-232 / USB (option) to a computer, software not provided, free download type «HYPERTERMINAL»
String ASCII / 2 seconds
Conversion by the software for access to Lotus 1-2-3 or Excel calculation software
|Maintenance||Distilled water cleaning of the measuring diaphragm after every use|
|Medium / sample temperature||0 ... + 30 ° C (40 ° C possible with a specific calibration on request)|