Calibration and Spectrum Troubleshooting: Troubleshooting Abnormal IMS Spectrums (Series Part 4 of 4)

Calibration and Spectrum Troubleshooting: Troubleshooting Abnormal IMS Spectrums (Series Part 4 of 4)

Outside of calibration activities, the IMS Spectrum is used to troubleshoot functional problems with AirSentry® II analyzers.

Possible indicators include:

Contaminated CDA

  • A double spectrum peak or bump before the dopant peak is seen while sampling CDA.
  • The dopant (reactant) peak is less than 500 bins high.
  • The dopant peak is broad.
  • A wide, double peak is seen (Acids analyzers only).

Some of these issues can be fixed easily with a filter replacement.

Incorrect Dopant Temperature

  • Target and dopant peaks have very different bin heights at 25 ppb.
    • If the dopant peak is smaller, the dopant temperature is too low.
    • If the dopant peak is larger, the dopant temperature is too high.

Dopant temperature adjustment should be adjusted to a specified range only by Particle Measuring Systems.

Blocked Orifice/Shutter Grid Malfunction/Missing Dopant

  • No visible peaks seen in the spectrum.

Incorrect Carrier Gas in Acids/Chlorides

  • A very “noisy” spectrum is seen with no obvious peaks (Acids or Chlorides analyzers only).

Out of Spec Pressure in CDA, Vacuum or Sample Flow

  • Peak is too far to the left or right.

Our service technicians are trained to assist with all functional issues. Contact your local Particle Measuring Representative if any abnormal IMS spectrums are seen.


Click here to learn more about innovative AMC monitoring solutions to help you quickly identify problems and their location before your product is contaminated: AirSentry II Point-of-Use Ion Mobility Spectrometer


See links to additional supporting resources below: 

On-Demand Webinar: Efficient troubleshooting techniques for AMC monitoring

Application Note: Calibration and Spectrum Troubleshooting


Want to read more? Jump to other released posts in this series:

Part 1 of 4: IMS Spectrum Introduction, Measurement and Calibration

Part 2 of 4: Zero Calibration

Part 3 of 4: Span Calibration

Part 4 of 4: Troubleshooting Abnormal IMS Spectrums (You are here!)

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