User manual HANNA INSTRUMENTS HI 38019

[. . . ] · Remove the cap and insert the reacted sample into the right hand opening of the checker disc. · Hold the checker disc so that a light source illuminates the samples from the top. · Keep the checker disc at a distance of 30-40 cm (1216") from the eyes to match the color. [. . . ] Chlorine present in water binds with bacteria, leaving only a part of the original quantity (free chlorine) to continue its disinfecting action. If the free chlorine level is improper with respect to pH, water will have an unpleasant taste and odor and the disinfecting potential of the chlorine will be diminished. Free chlorine reacts with ammonium ions and organic compounds to form chlorine compounds resulting in diminished disinfecting capabilities compared with free chlorine. Chlorine compounds together with chloramines form combined chlorine. Combined chlorine and free chlorine together result in total chlorine. While free chlorine has a much higher disinfectant potential, combined chlorine has a much higher stability and has a lesser volatility. Note: mg/L is equivalent to ppm (parts per million). · Insert one of the vials into the left hand opening of the checker disc. This is the blank. · Remove the cap and fill the Demineralizer Bottle with tap water. · Replace the cap and shake gently for at least 2 minutes. · Flip open the top of the Demineralizer Bottle cap. By gently squeezing the bottle, add demineralized water to the other vial up to the 20 mL mark. Replace the cap and shake to mix. 02/00 CHEMICAL REACTION The reaction between chlorine and the DPD reagent causes a pink tint in the sample which is proportional to the chlorine concentration. ISTR38019 · To measure total chlorine in the 0-3. 5 mg/L range, remove the disc, mirror and its holder, if pre-installed. Then install just the disc as shown here. · Use the pipette to fill each glass vial with 5 mL of sample (up to the mark) and insert one of them into the left hand 5 mL opening of the checker disc. · Add to the other vial demineralized water up to the 10 mL mark and shake to mix. Caution: Ultraviolet radiation may cause fading of colors. When not in use, keep the disc protected from light, in a cool and dry place. [. . . ] Rotate the disc while looking at the color test windows and stop when you find the color match. Read the value in the result window directly in mg/L (or ppm) of Chlorine. For best results: Perform the reading three times and take the average value (divide by 3 the sum of the three numbers). [. . . ]