pH – ANALYZER FOR THE PH VALUE IN WATER

The CONTROS HydroFIA pH is a flow-through system for the determination of the pH value in saline solutions and ideally suited for measurements in seawater. The autonomous pH analyser can be used in the lab or easily integrated into existing automated measuring systems on e.g. voluntary observing ships (VOS).

OPERATING PRINCIPLE

Basis for the determination is the change of the colour of the indicator m-Cresol purple in dependence of the sample pH value. For each measurement, a small volume of indicator dye is injected into the sample stream of which the pH value is then determined by means of VIS absorption spectrometry.

BENEFITS

Measuring the pH value using m-Cresol purple is an absolute measurement method. Combined with the technical implementation, this analyser is calibration-free and therefore suitable for long-term applications. Furthermore, the analyser can be used for monitoring of e.g. short-term biogeochemical processes.
The low reagent consumption makes long deployment times possible with only minimal maintenance requirements. Once the analyser runs out of reagents, the cartridges can be easily exchanged due to their user-friendly design. In addition, the low sample consumption enables the pH determination from small sample volumes.

HydroFIA pH data sheet

FEATURES

  • High accuracy
  • Drift free
  • Measurement cycles of approx. 2 min
  • Low sample consumption
  • Low reagent consumption
  • User-friendly reagent cartridges
  • One device for single measurements to
    autonomous long-term installations
  • Second inlet for regular standard measurements
  • Integrated acid flush for regular cleaning
    during operation

OPTIONS

  • Integration into automated measuring systems on VOS
  • Cross-flow filters for high turbidity / sediment loaded waters

  REFERENCES

GREAT ADVANCEMENT FOR PH MONITORING IN THE BALTIC SEA
The within the BONUS PINBAL project newly developed analyzer CONTROS HydroFIA pH is now available for precise, high-resolution and widespread pH monitoring even in freshwater regions.

INTERNATIONAL OCEAN SYSTEMS MAGAZINE

SPECTROPHOTOMETRIC PH DETECTION – THE FOUNDATION FOR THE CONTROS HYDROFIA PH
As a well proven and accepted method, the optical pH detection approach provides an accurate method that is in principle drift and calibration free being perfectly suited for longterm monitoring applications but also for use in the lab measuring discrete samples.

OCEAN SCIENCE, DOI 10.5194/OS-7-597-2011

IMPACT OF DISSOLVED ORGANIC MATTER AND HYDROGEN SULFIDE ON SPECTROPHOTOMETRIC PH MEASUREMENTS
This study gives evidence that natural H2S concentrations have no impact on optical pH measurements, while DOM can potentially interfere. However, when using short optical path lengths as e.g. used in the CONTROS HydroFIA pH, this effect can be considered as negligible.

LIMNOLOGY AND OCEANOGRAPHY METHODS, DOI 10.1002/LOM3.10227