Flame photometric detector (FPD) is a highly sensitive and selective detector in gas chromatography, mainly used for detecting compounds containing sulfur and phosphorus. To ensureFPD detectorThe following is a detailed daily maintenance manual for improving performance and extending its service life:

1、 Daily maintenance projects

1. Air path cleaning

Regularly inspect and clean the air circuit, including filters for carrier gas, hydrogen gas, and air, to prevent pollutants from entering the detector.

2. Optical path inspection

Regularly inspect the lenses and filters in the optical path, and clean them with appropriate solvents and dust-free cloths if they are contaminated.

Pay attention to protecting the filter to avoid scratches or damage.

3. Purity inspection of gas source

The use of high-purity gases such as carrier gas, hydrogen gas, and air is crucial for the performance of FPD detectors. It is recommended to use gas with a purity of not less than 99.99%.

Regularly check gas purity to ensure that gas quality meets requirements.

4. Avoid hydrocarbon impurities

Hydrocarbon impurities will burn in hydrogen rich flames, producing emission spectra that interfere with the detection of sulfur and phosphorus. Therefore, it is necessary to ensure that the gas source contains no or as little hydrocarbon impurities as possible.

5. Temperature adjustment of detector

　　FPD detectorThe working temperature is usually high to ensure sufficient combustion and excitation. However, excessively high temperatures may lead to the decomposition of certain compounds.

Therefore, it is necessary to adjust the appropriate detector temperature according to the measured substance.

6. Environmental humidity control

Due to the use of photomultiplier tubes in FPD detectors, excessive humidity may affect their insulation performance.

Therefore, the environmental humidity in the laboratory should be controlled within an appropriate range to avoid a decrease in detector performance caused by excessive humidity.

7. Ignition signal inspection

Regularly check the ignition signal to ensure that the flame state of the detector is normal. Abnormal ignition may affect detection sensitivity.

If ignition is difficult, the flow rate ratio of air and hydrogen can be adjusted appropriately to help ignite the flame.

8. Sample processing

For samples that are prone to adsorption and residue, such as organic sulfur compounds, it is necessary to inert the injection port to reduce the problems of decreased analytical sensitivity and increased detection limit.

9. Helium protection

If helium is used as the carrier gas, nitrogen needs to be used as a protective gas for blowing to prevent helium from infiltrating the photomultiplier tube and causing damage.

10. Solvent selection

Avoid using halogenated hydrocarbon solvents as they can produce corrosive substances and damage the detector during combustion.

2、 Key component maintenance

1. Replacement of ignition wire

After cooling down and shutting down, follow the instructions or maintenance manual to disassemble the FPD end cover assembly, remove the ignition coil connector, and replace the ignition wire and end cover assembly with new ones.

Ensure that there is no short circuit between the ignition coil and the instrument casing.

2. Filter replacement

After cooling down and shutting down, use a special tool to disassemble the parts of the FPD detector that fix the photomultiplier tube, and remove the filter and corresponding sealing ring.

Clean the filter port, reinstall the new filter and sealing ring in order, and secure the photomultiplier tube.

3、 Safety precautions

1. Prevent hydrogen gas leakage

Do not allow hydrogen gas to leak into the column thermostat during use to prevent explosion.

Do not introduce hydrogen gas before connecting the chromatography column, and turn off hydrogen gas before unloading the column.

When only one set of FPDs is used, be sure to block the other set with nuts.

2. Anti scalding measures

The FPD casing may be very hot during operation, do not touch the surface to prevent burns.

4、 Summary

　　FPD detectorDaily maintenance is key to ensuring its performance and extending its lifespan. By regularly cleaning the gas path, inspecting the light path, checking the purity of the gas source, adjusting the detector temperature, controlling the environmental humidity, checking the ignition signal, processing samples, selecting appropriate solvents, and replacing key components, the normal operation of the detector can be effectively maintained. At the same time, pay attention to safe operation to prevent accidents such as hydrogen leakage and burns.