Calcium Ion-Selective Electrode

Product image for Calcium Ion-Selective Electrode

The Calcium Ion-Selective Electrode (ISE) can be used to measure the concentration of Calcium (Ca2+) in aqueous samples.


Data from the Calcium ISE can give a good indication of hardness of water (as Ca2+). The concentration of Calcium is also used as an endpoint indicator in EDTA-Ca/Mg hardwater titrations.

The Calcium ISE has a combination-style, non-refillable, gel-filled electrode. Like all other PVC ISE membranes, the membrane on the ISE has a limited life expectancy. However, the replaceable module of ISE allows you to simply discard the used membrane module, and replace it with a new one.

Note: We recommend that you do not purchase ISE replacement modules too far in advance of their expected time of use as degradation occurs while they are stored on the shelf.

Important: Ion-Selective Electrodes require good chemical technique and careful calibration to obtain accurate results; they are not recommended for middle school or elementary students.



  • Range: 1 to 40,000 mg/L or ppm
  • Accuracy: ±10% of full scalre (calibrated 10 to 1000 mg/L)
  • pH Range: 3 to 10
  • Interfering Ions: Pb2+, Hg2+, Sr2+, Cu2+, Ni2+
  • Electrode Resistance: 1 to 4 MΩ
  • Electrode Slope (log voltage vs. concentration): +28 mV/decade
  • Temperature range (can be placed in): 0 to 50°C (no temperature compensation)
  • Minimum immersion: 1.1 inch
  • Electrode Length: 155 mm
  • Body Diameter: 12 mm
  • Cap Diameter: 16 mm
  • Cable Length: 100 cm

Download the user manual for full specifications

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What's Included

  • Vernier Calcium Ion-Selective Electrode
  • 30 mL bottle of Calcium Low Standard (10 mg/L)
  • 30 mL bottle of Calcium High Standard (1000 mg/L)
  • Short-term ISE soaking bottle
  • User manual


The Calcium Ion-Selective Electrode requires a compatible interface and software to collect data. Interface and software sold separately. Getting started with probeware »

Compatible Interfaces

The Calcium Ion-Selective Electrode is compatible with these interfaces:

Ordering Information

All prices are for U.S. educators.

    NameOrder CodePriceQuantity
    Calcium Ion-Selective ElectrodeCA-BTA$179
    Optional Accessories
    Electrode SupportESUP$10

    Related Products

    Educational use only: Vernier products are designed for educational use. They are not appropriate for industrial, medical, or commercial applications. Product usage disclaimer »

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