How to Calibrate a PH Pen

pH stands for "potential for hydrogen." The pH scale is used to test the acidity or alkalinity of a solution by measuring it on a scale from 0 to 14. According to the pH scale, a solution measuring 7 is neutral. The greater the value over 7, the more basic the solution; the lower the value under 7, the more acidic the solution. A pH pen is commonly used to test the pH balance of various solutions, but the tool must be properly calibrated to ensure an accurate reading.

Things You'll Need

• pH Pen
• Buffer or reference solution with a pH of 7
• Glass beaker or container
• Distilled water
• Squeeze bottle
• Soft tissue
• Jewelry screwdriver

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Instructions

• 1

  Rinse the pen's electrode, which is the glass probe at the end of the pen, by pouring distilled water onto it from a squeeze bottle.

• 2

  Gently blot the electrode dry with a soft tissue. Ensure that there is no water left on the electrode.

• 3

  Turn the pen on by clicking the "on" button found at the top of the pen.

• 4

  Immerse the pen into the glass beaker containing the reference solution with a pH of 7.

• 5

  Gently stir the pen in the solution while waiting for the reading to stabilize.

• 6

  Use the screwdriver to turn the small screw in the hole in the back of the pen until the pen reads precisely "7."

• 7

  Remove the pen from the reference solution and rinse the electrode again with distilled water. Wipe it again with a soft tissue.