Aquation’s pHalkon monitors pH using a fluorescence-based technique. Excitation light and fluorescence emission are conveyed through a fibre optical cable within the housing. A pH-sensitive fluorophore is attached to the outside of the housing, this fluorophore responds to changes in pH with altered fluorescence lifetime decay. This is compared with a second fluorophore unaffected by pH; the measured phase difference is compared against phase differences measured during calibration. From these phase differences pH is calculated. All measurements are temperature compensated. Electrical conductivity/salinity is also measured and is used to approximate alkalinity, enabling calculation of seawater carbonate chemistry parameters.
Aquation’s pHalkon pH monitor measures pH, temperature and salinity. It is designed for marine and estuarine applications where knowing short-term changes in pH is important. The salinity sensor enables estimation of seawater carbonate chemistry including carbonate saturation states. pHalkon: pH, alkaline, ocean, numerics.