Colorimeter Guide: Measuring Chlorine Levels in Water

Colorimeters often, though not exclusively, test the levels of chlorine in solutions; drinking water, wastewater and sea water are common solutions tested. Using a reagent, DPD (N, N-diethyl -- p -- phenylendiamine) for example, colorimeters show in milligrams per liter (mgL) how much chlorine is present in a solution by filtering out portions of the visible light spectrum isolated by the solution's reaction with the reagent. If samples are prepared carefully, colorimeters produce quick and easy readings of water samples to aid scientists, campers or anyone simply interested in the quality of water.

Things You'll Need

• Solution (water)
• Reagent
• 2 cuvettes, 10 milliliter
• 50 milliliter beaker

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Instructions

• 1

  Set the range of the colorimeter from 0 to 2.00 mg/L.

• 2

  Pour 20 to 30 milliliters (mL) of water into the 50 mL beaker.

• 3

  Fill one of the cuvettes with a water sample (no reagent) to the 10 mL line and place it in the colorimeter.

• 4

  Reset the colorimeter to 0.00 grams per milliliter.

• 5

  Fill the second cuvette with water to the 10 mL line, then add the reagent.

• 6

  Remove the first cuvette from the colorimeter and replace it with the second.

• 7

  Read the amount of chlorine in mg/L present in the water.