Apparatus and method for measuring hydrogen peroxide in water

An apparatus for measuring hydrogen peroxide in water using a colorimetric assay method comprising:

• a. a measurement cell for containing a water sample;
• b. a light transmitter configured to emit light at a selected wavelength at the measurement cell;
• c. a photodiode receiver configured to receive light passing through the measurement cell;
• d. a reagent in a reagent vial, consisting of:
• a reagent compound configured to react with hydrogen peroxide to form a reaction product, the reaction product adapted to absorb light at the selected wavelength proportional to the amount of hydrogen peroxide in the water sample,
• a surfactant, and
• a solvent;
• and
• e. a first network of pipes connecting the source water to a buffer jar, the buffer jar to a supply valve, the supply valve to the measurement cell, and a second network of pipes connecting the reagent vial to a reagent valve, the reagent valve to the measurement cell, and the measurement cell to a drain valve;
• f. a control unit;
• wherein the control unit is configured to cause a first colorimetric measurement of a first water sample free of reagent and a second colorimetric measurement of a second water sample mixed with reagent, then determines the difference between the first and second measurements and compares the difference against a pre-determined standard curve of diluted hydrogen peroxide to determine and report the concentration of hydrogen peroxide in the water sample, accurate to 0.1 mg/L.