pH Sensor Spots


  • Measurement range pH 4.0-6.0
  • Sensor spots (8 pcs.) 5mm in diameter
  • Precalibrated for plug & play measurements
  • Contamination-free due to non-invasive measurement
  • Autoclavable

pH sensor spots allow pH measurements over a defined pH range of 4-6 in closed sample containers with contactless read-out through a transparent window (glass, acryl glass), with special adapters and optical fibers for fiber-optic meters from PyroScience. This enables incubations in closed systems, preventing potential contamination and simplifying pH monitoring without sampling, also in combination with oxygen and temperature sensor spots.

Our new precalibrated pH sensors can be used once without manual calibration in combination with a FireSting-PRO meter that enables pre-calibration pH measurements (older FireSting-PRO meters can be upgraded). Pre-calibration measurements are intended for single-use applications and only work in combination with the bare optical fiber SPFIB-BARE (NOT SPFIB-LNS). After first use of the precal pH sensor, the sensor can be continued to use after a manual calibration (mandatory). For precision measurements in other applications or in combination with the lens optical fiber SPFIB-LNS, a manual 2-point calibration of the pH sensor must be performed before first use.

pH range 4.0-6.0 This sensor is specified for the pH range 4.0-6.0. For detailed specifications, see the respective pdf file in the Downloads tab.

Precalibrated pH measurements In combination with the bare optical fiber SPFIB-BARE only, the pH sensor spots can be used once without a manual calibration. For precision pH measurements or in combination with the lens optical fiber SPFIB-LNS, a manual sensor calibration is mandatory before the measurement.

No reference electrode needed. Based on the optical sensing principle (REDFLASH technology), the pH value is measured directly on the sensor surface without a reference electrode.

Optical isolation.This sensor type is equipped with an additional optical isolation protection layer. This layer reduces enhanced sensor aging and interference with the measurements in applications at high ambient light (e.g. direct sunlight, illuminated samples) and in fluorescing / light-sensitive samples.

Easy calibration. Calibration of the pH sensors is performed at pH 2 and pH 11 using our easy-to-use calibration capsules (PHCAL2 and PHCAL11). For detailed calibration recommendations, please refer to the manual in the downloads tab.

Applications. To get an overview of potential applications and to see our sensors in action, please visit our Applications site!

Price List

Please visit our accessories site for all available accessories for our contactless sensors.

Optical Fiber


  • For contactless sensor readout
  • Optical fiber core Ø = 1mm
  • Ca. 1m length
  • With ST-connector and bare fiber end
  • To measure through 0-2mm thick materials

Optical Fiber with Lens


  • For contactless sensor readout
  • Ca. 1m length
  • through thick walled containers
  • Compatible to SPADBAS
  • With ST-connector for FireSting devices

Basic spot adapter


Silicone Glue


  • Transparent silicone glue Elastosil E43, (ca. 90 ml)
  • For fixing sensor spots or SPADBAS at container walls

Calibration Capsules (pH 2)


For obligatory acid calibration of optical pH sensors. Each capsule results in 100mL calibration solution (PU=10).

Calibration Buffer Capsules (pH 11)


For recommended basic calibration of optical pH sensors. Each capsule results in 100mL calibration buffer solution (PU=10).

Every PyroScience pH meter is generally compatible to this sensor. Pay attention to the correct optical fiber for contactless readout. All options can be found under accessories for contactless readout. Use the link below to get a list of all compatible meters. Select additional requirements to find the optimal meter for you and your application!


Exemplary Setup


Choose the multi-analyte FireSting-PRO (4 chan.) with the pH sensor spots PHSP5-PK5

  • 4 freely configurable optical channels
  • + oxygen & temp sensor support

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