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Ocean Optics
Worldwide Headquarters
Largo, Florida, USA

+1 727-733-2447

Sales, Service
& Support Facility
Duiven, The Netherlands

+31 26-319-0500
+33 442-386-588

Ocean Optics GmbH Sales,
Service & Support Facility
Ostfildern, Germany

+49 711-34-16-96-0

Sales Support
for the
United Kingdom

+44 1865-811118

Sales, Service
& Support Facilities
Shanghai, PRC – Beijing, PRC

+86 21-6295-6600


pH Sensing

pH_heroTake a look around you. Nearly every object you see was made at a plant or facility that needed to monitor the pH of a stream at some point in the process. pH plays a far greater role in our lives than we realize, affecting and enabling chemistry throughout our daily lives. It plays a role in the ocean’s carbon cycle, affects the functioning of hemoglobin, and determines the rate of many industrial processes. We depend on it to simply exist, as levels outside the narrow range of pH 5 – 9 are hostile to life.


Accurate pH sensing allows us to monitor and fine-tune chemical processes, protect the environment and the living things within it, and study biological systems. Electrode-type meters have long been the standard, but the development of optical pH sensors has improved the response time and range of chemical compatibility, as well as enabling non-contact measurements.


Ocean Optics began its story in 1989 with the pHish Doctor, an indicator patch to monitor pH in fish tanks. So it is only fitting that we have come full circle to develop a sol-gel based optrode for pH measurement that is capable of high-resolution measurement throughout the biological range (pH 5 – 9). Our pH probes and patches offer versatility and ease of use, while minimizing sensitivity to ionic strength.


Just as our pH sensors have moved beyond the fish tank, we invite you to think outside the box about how they can help you.



  • Multiple form factors: pH sensor chemistry can be applied to probes, non-invasive patches, cuvettes, and other materials
  • Non-invasive option: self-adhesive patches can be placed on the interior of a transmissive container and read through the vessel wall
  • Low maintenance: sensors require no special storage solutions, unlike traditional electrodes
  • Biocompatible: ideal for sensing in the biological range (pH 5 – 9), and pH sensor chemistry has been USP Class VI certified
  • High resolution: sensors can resolve to 0.01 pH unit with certain optical configurations


Other Common Applications

  • Biological environments: biofermentation processes, cell culture monitoring, bioreactor monitoring
  • Biomedical & life sciences: pH titrations, low ionic strength samples, blood and other bodily fluid analysis, tissue analysis, microtiter plates
  • Food process & storage monitoring: beverage packaging, vacuum-packaged foods, vegetable oils, wine fermentation
  • Pharmaceutical & chemical processing: pharmaceutical fermentation
  • Environmental & ecological: aquaculture applications, marine organisms, natural waters (marine, surface), soils and sediments, waste water treatment
  • Industrial: general manufacturing of products, power plant cooling water

Application Note:

Application Blog Post: Monitoring Oxygen and pH during E. coli Fermentation (November 2015)

Featured Products for pH Sensing:

Oxygen and pH Setup

Flame Spectrometer We recommend configuring the Flame spectrometer for visible measurements from 350-1000 nm and using a 50 µm entrance slit.
HL2000 Tungsten halogen source provides VIS-NIR illumination.
RE-BIFBORO-2 Bifurcated optical fiber with borosilicate fiber bundle has one fiber leg to illuminate the patch and one fiber leg to collect the response.
PH-BCG-REFLECT These reflective pH patches can be used with colored or turbid samples, and are meant to be applied to the inner wall of a clear vessel or process flow. Each order comprises a pack of 5 sol gel-entrapped bromocresol green pH sensors.

How can pH levels be measured?
How does an Ocean Optics pH sensor work?
What light source should I use for pH sensing?
What is the best sampling optic for my pH measurement?
What fibers should I use for routing?
What spectrometer should I use for detection?
What software do I use with my pH sensor?
How do I calibrate my pH sensor?
What is the algorithm for pH calibration and calculation?
How can I make the best pH measurement?
How can I safely clean and sterilize my pH probe?
What are some tips for handling and working with pH patches?
What is the precision of my pH sensor?
What chemicals are incompatible with pH sensors?
Is photobleaching an issue?
What does USP Class VI Certification mean?
What is the maximum temperature my pH sensor can withstand?
Are there sensors for other pH ranges?
Do I need temperature compensation for my pH probe?
pH Sensing

Education Kits for Science

Education Kits for Science

Spectroscopy Experiment Kit for Teaching STEM Labs
USB2000+ (Custom)

USB2000+ (Custom)

Custom Configured Spectrometer for Setup Flexibility
USB4000 (Custom)

USB4000 (Custom)

Custom Configured for Maximum Flexibility
EMBED Spectrometer

EMBED Spectrometer

Robust, Stable Spectrometer for OEM Applications
HL-2000 Family

HL-2000 Family

Tungsten Halogen Light Sources for the Vis-NIR
74-series Collimating Lenses

74-series Collimating Lenses

Single and Achromatic Lenses
T200- and T300-Series Transmission Dip Probes

T200- and T300-Series Transmission Dip Probes

General Purpose Probes for the Lab and Other Environments
TP300-Series Transmission Probes

TP300-Series Transmission Probes

Transmission Dip Probes for Hostile Environments


Transmissive pH Dip Probe Kits


Transmissive pH Sensing Patches


Reflective pH Patch Kit
ACH-CUV-VAR Lens Holder

ACH-CUV-VAR Lens Holder

Adjustable Collimating Lens and Cuvette Holder


Rugged Watertight Carrying Case