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-4H-Jena engineering GmbH has become the only commercial provider with the ability to offer large-scale purification of meta-Cresol Purple (mCP) for spectrophotometric seawater pH measurement. The capability is now available in direct support of its CONTROS HydroFIA™ pH analyser, addressing a long-standing challenge in marine carbon system monitoring.
Spectrophotometric pH measurement using indicator dyes such as mCP is widely recognised for its precision and suitability for high-quality ocean monitoring. However, impurities in commercially available indicator dyes can introduce systematic bias, even when apparent precision is high. Manufacturer and batch-dependent variability has been shown to shift reported pH values by up to 0.01 units, limiting data comparability and undermining confidence in long-term time series.
Until now, there has been no commercially available, scalable source of purified mCP. Laboratories and monitoring programmes have either relied on limited research-grade supply or undertaken their own purification, often at significant cost and effort. These approaches are typically time-intensive and difficult to scale for global monitoring needs.
By establishing the world’s first commercial in-house purification capability, -4H-Jena engineering is removing this bottleneck for users of the CONTROS HydroFIA™ pH system. The company can now deliver rigorously quality-controlled, ready-to-use purified mCP as part of its overall solution, reducing the technical and operational burden on customers while improving traceability and comparability of pH data
“High-quality indicator dye is fundamental to unlocking the full potential of spectrophotometric pH measurements,” says Dr. Katharina Seelmann, Project Manager Research & Technology Management, -4H-Jena engineering GmbH. “By offering purified mCP as a commercially available product, we are eliminating a key source of systematic bias and giving monitoring programmes greater confidence in the reliability and comparability of their data. This is an important step towards more robust long-term ocean observation.”
For operators of the CONTROS HydroFIA™ pH analyser, the development strengthens the system’s position as a complete and traceable measurement solution. By combining proven spectrophotometric technology with a secure supply of high-purity indicator, -4H-Jena engineering enables more consistent data across platforms and programmes, supporting applications from coastal monitoring to open-ocean research and high-resolution time-series studies.
Visitors to Oceanology International 2026 are invited to discuss this new capability and other recent -4H-Jena engineering developments on stand B201.