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 Tech Talk
If done correctly, measuring pH can provide important information on practically every step of water treatment. So, don’t be a sinner and avoid the following: 1. Wrong electrode for the job. Pick the right electrode for your application: Clean Water Lab- glass, refillable, single-junction electrode Dirty Water Lab- glass, refillable, double-junction electrode Clean Water Field- epoxy, sealed, single junction electrode Process and Influent-epoxy, refillable, double-junction electrode Wastewater- epoxy, refillable or flushable, double junction electrode Sludge- epoxy, flushable, double junction electrode. 2. Reused pH buffers. solution exposed to air absorbs carbon dioxide, changing the pH. A pH 10 buffer can change more than a half pH unit per one afternoon. 3. Infrequent calibrations. Perform a two- or a three-point calibration with fresh pH buffer at least once every eight hour shift to maintain accuracy. 4. Forgetting temperature compensation. pH readings vary with temperature, so temperature compensation is required to standardize pH values. 5. Using dehydrated electrodes. When you are done measuring, rinse and soak the pH electrode in electrode storage solution. pH electrodes must always be stored wet. 6. Using dirty electrodes. Keep your electrode clean and your reference junction flowing. For a clogged reference junction and dry gel electrodes, heat a 0.1M KCl solution to about 50¡C, and let slowly return to room temperature with electrode in solution, rinse and soak in storage solution. 7. Neglected fill solutions. Replace fill solution in refillable electrodes every 2 to 3 weeks. The level of fill solution should be kept higher than the level of sample being measured. Keep the fill hole open during measurement and storage (the only exception is for long term storage). Of course there are many quirky samples/applications, but luckily you can call USABlueBook’s Technical Support at 800-548-1234 for additional help and information. |
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