What could cause very small peaks when running samples and standards on a Lachat Flow Injection Analysis Method?

Document ID

Document ID TE7989

Version

Version 2.0

Status

Status Published

Published Date

Published Date 06/07/2018
Question
What could cause very small peaks when running samples and standards on a Lachat Flow Injection Analysis Method?
Summary
Small peaks when running Lachat Flow Injection Analysis (FIA) methods.
Answer
If peaks are significantly smaller than the support data on a Lachat FIA method, there are several things that could be at fault:
  • Verify the valve timing. Run dye as a sample and verify the sample loop is being filled properly and injected into the manifold.
  • There could be a valve issue. Try using a different injection valve.
  • Verify the reagents are fresh and free from contamination. Old source chemicals can also be a concern even if the reagent was freshly prepared.
  • Verify the pH of the reagents, samples and standards against the method.
  • Check the standard source and preparation.
  • Verify the correct sample loop for the method is used.
  • Verify the correct pump tubes are being used. Check both the size and the material.
  • Verify the correct detector filter is used.
  • Try using a different detector to verify the detector is functioning properly.
  • Check the baseline voltage.
  • Check the pump to verify it is working at the correct speed.
How is valve timing optimized on the Lachat QC8500 FIA?
 

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