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Diagnosis and Solution Sharing of Common Malfunctions in Molecular Fluorescence Spectrometer
Date: 2025-10-09Read: 3
Molecular fluorescence spectrometer over excites molecules to produce fluorescence, accurately measuring their emission spectra, intensity, and lifetime. Its optical system is precise, the light source is sensitive, and the sample requirements are high. During use, problems such as weak signal, high noise, and wavelength shift often occur. Mastering the diagnosis and solution methods of common faults in molecular fluorescence spectrometers is the key to ensuring continuous and accurate operation.
Problem 1: Low or no fluorescence signal intensity
Check the light source: Confirm whether the xenon lamp is lit and whether its lifespan has expired (usually 500-1000 hours), and replace it if necessary;
Optimize parameters:
Increase the width of the excitation/emission slit to increase the light flux;
Adjust the voltage of the photomultiplier tube (PMT) to an appropriate range (to avoid introducing excessive noise);
Sample issue:
Confirm that the sample has fluorescent activity, and concentrate it appropriately when the concentration is too low;
Check if the solvent contains fluorescent quenchers (such as halogens or heavy metal ions);
Optical alignment: Clean the quartz colorimetric dish to ensure there are no fingerprints, scratches, or contaminants.
Problem 2: High background noise or baseline drift
Dark current correction: Run the "dark scan" function to deduct the instrument background signal;
Light source stability: Preheat the xenon lamp for 15-30 minutes and wait for the light intensity to stabilize before testing;
Environmental interference: Turn off strong indoor light (especially sunlight) to avoid stray light entering;
Electronic noise: Check if the grounding is good and keep away from electromagnetic interference sources (such as centrifuges and microwave ovens).
Question 3: Abnormal spectral peak shape (peak shift, bimodal, tailing)
Wavelength calibration: Use standard fluorescent substances (such as quinine sulfate and rhodamine B) to calibrate the excitation and emission wavelengths;
Slit setting: too wide leads to a decrease in resolution, while too narrow reduces signal-to-noise ratio, requiring balanced optimization;
Sample issue:
High concentration samples may exhibit self absorption or internal filtration effects and require dilution;
The solution is turbid or contains particles that cause scattered light interference, and should be centrifuged or filtered.
Problem 4: The instrument cannot start or the software is unresponsive
Power check: Confirm that the host, xenon lamp power supply, and computer are connected properly;
Restart the system: Shut down all devices, wait for 1 minute, and then restart them in sequence;
Drivers and software: Check USB/Ethernet connection, reinstall device drivers or analyze software.