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Van London Company
10540 Rockley Road
Houston, TX 77099
USA

(Toll Free) 800-522-7920
(voice) 832-456-6641
(fax) 832-456-6642

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Brief Guide to Troubleshooting Common Measurement Problems with Simple Causes TEXT SIZE: A A A    PRINT THIS PAGE   EMAIL THIS PAGE

 

READINGS ARE NOT REPRODUCIBLE
  • Is there sample carryover?
  • Are there sample interferences or complexing agents present?
  • Is the reference electrode junction contaminated?
SLOW RESPONSE (READINGS SLOWLY CHANGING)
  • Was the electrode stored in the wrong solution?
  • Was the electrode poisoned by the sample?
OUT OF RANGE READING
  • Is the electrode plugged into the controller properly?
  • Is there a reference electrode present?
  • Is there enough fill solution left in the reference electrode?
  • Is the electrode placed in the sample solution?
LOW SLOPE OR NO SLOPE
  • Are the standards too old, contaminated, or made wrong?
  • Has the sample pH been adjusted properly to the operating range of the electrode?
  • Is there an air bubble on electrode surface?
  • Is the controller okay?
  • Is there enough fill solution left in the reference electrode?
NOISY RESPONSE (READINGS RANDOMLY CHANGING)
  • Is the controller grounded?
  • Is there an air bubble on electrode surface?
  • Is the controller operating properly?
  • Is there enough fill solution left in the reference electrode?
DRIFTY RESPONSE (READINGS CONTINUOUSLY CHANGING)
  • Is there excessive leaking at the reference electrode junction?
  • Is the reference electrode junction clogged?
  • Was the sensing membrane poisoned by the sample?
  • Are there temperature problems?
  • Is the sample too concentrated?
  • Does the sensing membrane need conditioning?
INACCURATE READINGS (BUT CALIBRATION IS OK)
  • Are the standards incorrect?
  • Was the sample pH adjusted properly?
  • Is there sample carryover?
  • Are there sample interferences or complexing agents present?