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Home > Products > Oxygen and pH Sensors > pH Sensors > pH Measurement Systems

pH Measurement Systems

Transmissive pH measurement systems allow light to pass through the sample during measurement, while reflective pH measurement systems prevent light from ever interacting with the liquid by making their measurement through a vessel wall. Both approaches can use the same basic system components, so the choice really depends on your application.

Light Sources

Any visible-range light source can be used with Ocean Optics pH sensor products. The key analytical wavelength is 620 nm, but wavelengths within ±10 nm of this may be used. Baseline correction requires any wavelength above 750 nm, though 510 nm can alternatively be used for systems using a white LED as the source.


Any spectrometer covering the visible range can be used for optical pH measurements. You may choose either a UV/VIS or VIS/NIR spectrometer configuration based on your specific application, field of study, or anticipated future applications. For example, those working in life science and studying proteins may choose a UV/VIS spectrometer for its versatility in use for both pH measurements and UV protein absorbance studies. Conversely, someone working with river water to assess sediment size or type may choose a VIS/NIR configuration to support those measurements as well. Your optical pH sensor system is extremely valuable as it also doubles as a world-class miniaturized spectroscopy platform.

  • Choose a slit size of 50 μm or smaller when using Smart pH Cuvettes or a transmissive pH dip probe
  • Choose a slit size of 50 – 100 μm when using reflective pH patches


Transmissive pH Sensing Patches
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