Ion Selective Electrode - Calcium

Order code

Accurately measure calcium

  • Fast, accurate, economical
  • Superior, stable PVC membrane
  • Fast response
  • 2mm diameter tips
  • Interchangeable tip holder
  • Each kit includes 3 electrode tips and MicroFil filling syringe


  • Inexpensive
  • Use to measure various ions in biological media


  • Detection of ions in vivo or in vitro for biological applications

These highly stable electrodes ac­cu­rate­ly measure cal­ci­um, po­tas­si­um, hydrogen and TPP (Tetraphenylphosphonium) ion activity. Tips consist of 2 mm di­am­e­ter plas­tic tubes sealed at one end with an ion-sen­si­tive mem­brane. After filling with elec­tro­lyte so­lu­tion, you can in­sert the tube into the hold­er and con­nect it to a pH meter. Tips and hold­ers are in­ter­change­able, so one tip may be re­placed with an­oth­er sensitive to a dif­fer­ent ion. Replac­ing a tip takes less than a minute. Elec­trode tips nor­mal­ly last sev­er­al months, when stored proper­ly in sa­line so­lu­tion. When re­place­ment is neces­sary, only the tip needs be re­placed.

Kwik-Tip electrodes are available separately and as kits. Each “KWIK” Elec­trode Holder kit includes a reus­able hold­er and three re­mov­able tips. In addition to a 4-foot BNC ca­ble and an electrolyte filling syringe; “TIP” Elec­trode Kits con­tain three elec­trode tips for a specific ion. A separate ref­er­ence electrode, such as WPI’s Dri-Ref™, is also required.

If your pH meter requires a US Standard connector, you will also need Part 3508 (BNC-to-US pH Standard adapter).

Color Code
Filling Solution
Min. Slope/Decade
Concentration Range
Selectivity Coeffiecients (-log)
Calcium Green 0.1M CaCl2 28mV 0.1 - 10-6.75M Na+ 5.5, K+ 5.4, Mg++ 4.9
Hydrogen Orange 1M Citric acid, 0.01M NaCl, pH 5.6 54mV pH 5.0-12 Na+ 10.4, K+ 9.8, Ca++ 11.1
Potassium Yellow 0.1M KCl 54mV 0.1 - 10-4.5M Na+ 4.0, Ca++ 3.9, Mg++3.0
TPP+ Purple 10mM TPP+ 54mV 0.001 - 10-4M K+ 6.0



A.S. Murphy, W.R. Eisinger, J.E. Shaff, L.V. Kochian, L. Taiz "Early Copper-Induced Leakage of K+ from Arabidopsis Seedlings Is Mediated by Ion Channels and Coupled to Citrate Efflux1" Plant Physiology 121. 1999: 1375-1385

More Choices:
  1. Micro Dri-Ref Reference Electrode
    Micro Dri-Ref Reference Electrode
  2. Dri-Ref Reference Electrode, 4.7 mm
    Dri-Ref Reference Electrode, 4.7 mm
  3. Dri-Ref Reference Electrode, 4.7 mm (short)
    Dri-Ref Reference Electrode, 4.7 mm (short)
  4. Dri-Ref Reference Electrode with Luer Tip
    Dri-Ref Reference Electrode with Luer Tip
  5. Flexible Dri-Ref Reference Electrode
    Flexible Dri-Ref Reference Electrode
  6. Electrode Holder for KWIK-Tips
    Electrode Holder for KWIK-Tips
  7. Super Dri-Ref Reference Electrode
    Super Dri-Ref Reference Electrode
  8. Calcium Electrode Tips, Replacement
    Calcium Electrode Tips, Replacement
  9. Dri-Ref Reference Electrode, Short
    Dri-Ref Reference Electrode, Short
  10. Hydrogen Electrode Tip, Replacement
    Hydrogen Electrode Tip, Replacement
  11. Dri-Ref Reference Electrode, 2 mm
    Dri-Ref Reference Electrode, 2 mm
  12. TPP Electrode Tips, Replacement
    TPP Electrode Tips, Replacement

This product requires the use of a reference electrode, like the DriRef-2. For a complete list of the DriRef electrodes, refer to the Accessories tab.


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