Why is my measurement response low at high concentrations?
Most likely cause: Leakage in sampling line or internal tubing This dilutes the sample and leads to underestimation.
What does it mean if FID ignition fails?
Possible causes include: Incorrect H₂ or air flow rates Leaks in the system Blocked FID nozzle Faulty ignition wire or voltage output In real use, 80% of ignition failures are flow or leak related—not hardware failure.
What should be done before shutting down the instrument?
Before shutdown: Purge with clean ambient air for 3–5 minutes Ensure no high-concentration residue remains Otherwise: VOCs may condense in tubing This leads to memory effects and false readings
Why does the instrument include oxygen and humidity correction?
Because: FID response is affected by oxygen concentration Water vapor dilutes hydrocarbon concentration These corrections ensure results are: Comparable Closer to regulatory reporting basis (dry gas, corrected values)
How is span calibration performed?
Use a standard gas close to sample concentration (≈80% of span) Inject via sampling line or span port Select a stable reading and input standard concentration
Why is zero calibration necessary and how is it done?
Zero calibration ensures the baseline of the FID is accurate. Perform after stabilization Takes about 30 seconds Can be done via “Zero Calibration” or Auto Zero function
What should I check before starting the instrument?
Before startup, you should: Ensure all tubing and cables are properly connected Check filters on the sampling line Confirm H₂ cartridge is installed and connected Make sure power supply meets requirements
How long should the instrument be preheated before measurement?
The instrument typically requires at least 15–20 minutes of preheating after ignition to stabilize before performing zero calibration or measurements.