PH ph Ph pH



pH = -log10[H+]




Fundamentals of pH





pH Determination




pH Scale




How Do We Measure pH?




How Does a pH Meter Work?




Measuring Tools




How Does a pH Meter Work?








pH Meters




Sample Collection




Bench pH Measuring




Our Procedure

  1. Calibrate lab pH meter
  2. Sample collection throughout plant/distribution system
  3. Between measurements, rinse electrodes with distilled water and then with the next sample to be measured
  4. Pour sample in beaker and immerse electrode
  5. Add magnet, turn on stir plate
  6. Record pH and temperature when meter says ready/hold
  7. When finished ensure electrode is placed in storage solution



How Do We Know Our pH Meters Are Reading Correctly?







Electrode Do's and Don'ts

  • Do store electrode in electrode storage solution
  • Do not store electrode in distilled water
  • Do calibrate meter daily
  • Do not leave exposed to air
  • Do keep electrode moist
  • Do not wipe electrode but blot with lint free tissue




Replace Your Electrode



Factors Affecting pH



Inline vs Bench pH Measurement

Inline pH Analyzers Bench Top Meters
  • continuous contact with the sample
  • influenced by exposure to atmosphere so you may experience "drifting"
  • conditioned to the process stream
  • gain or loss of CO2 may result in different pH readings
  • does need calibration and maintenance
  • does need calibration and maintenance daily
  • should be checked periodically against bench top meter


*If comparing the two, +/- 0.1 is ideal but +/- 0.2 is realistic




pH Facts




Chemicals That Raise pH



Chemicals That Lower pH