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The Most Common Faults and Maintenance Methods of Uv Spectrophotometer

Date:2020-08-19

UV spectrophotometer is one of the most popular spectrometers in laboratories. Due to its high sensitivity, good selectivity, high accuracy, and wide range of applicable concentrations, the most important thing is the low cost of analysis, easy operation, and fast speed. Widely used, it has played an important role in the analysis field for a long time. But everyone will also worry about changing the light source. Every time there is a difference in the data, they feel that the light source is in trouble. Today, the Spectrophotometer Supplier will share with you a summary of troubleshooting methods on some issues with the life of the light source.

Light source part

1

Trouble: The deuterium lamp does not light up

Reason: the life of the deuterium lamp has expired (this reason has the highest probability).

Check: The filament voltage and anode voltage are both, and the filament may not be broken (you can see that the filament is red).

Disposal: Replace the deuterium lamp.

2

Trouble: The tungsten lamp does not light up

Reason: The filament of the tungsten lamp is burned out (this reason has the highest probability).

Check: There is working voltage at both ends of the tungsten lamp, but the lamp does not light up; remove the tungsten lamp and use a multimeter to test.

Disposal: Replace with new tungsten lamp.

3

Trouble: The tungsten lamp does not light up

Reason: No lighting voltage.

Check: The fuse is blown.

Disposal: Replace the fuse, (if it blows again after replacement, check the power supply circuit).

4

Trouble: The deuterium lamp does not light up

Reason: Deuterium lamp ignition circuit failure.

Inspection: During the ignition process of the deuterium lamp, the filament generally needs to be preheated for a few seconds, and then the anode and cathode of the lamp can be ignited and discharged. If the lamp flashes or flashes continuously at the beginning of ignition It is still the same after replacing the new deuterium lamp. It may be that the circuit is faulty. The high-power transistor for lamp current adjustment has the greatest chance of damage.

Disposal: need professional repair.

UV Spectrophotometer

UV spectrophotometer

Note on UV use

1. The absorption pool used must be clean and pay attention to paired use. The measuring flask and pipette should be calibrated and washed before use.

2. When taking the absorption cell, your fingers should hold both sides of the frosted glass surface, and the sample should be placed at 4/5 of the cell body. When using volatile solutions, it should be covered. The transparent surface should be covered with lens cleaning paper from top to bottom. Wipe clean and check that there should be no solvent residue. Pay attention to the same direction when placing the absorption cell in the sample chamber. Rinse it with solvent or water after use, dry it and store it away from dust.

3. The concentration of the test solution should be between 0.3 and 0.7 unless the species has been indicated.

4. Unless otherwise specified, the same batch of solvent used to prepare the test solution should be used as a blank control during the measurement, and a 1cm quartz absorption cell should be used to measure the absorbance at several points within ±2nm of the specified absorption peak or by the instrument Automatic scanning measurement near the specified wavelength to check whether the absorption peak position of the test product is correct, and the wavelength with the maximum absorbance is used as the measurement wavelength. Unless otherwise specified, the maximum absorbance wavelength should be measured under the category The wavelength is within ±2nm.

5. Two copies of the test substance should be taken. If it is a reference substance comparison method, two copies of the reference substance should generally be taken.  In parallel operation, the deviation of each result from the average value should be within ±0.5 %.

6. The slit width of the selected instrument should be less than the half-width of the absorption band of the test product, otherwise the measured absorbance value will be lower. The slit width should be selected to reduce the absorbance of the test product when the slit width is reduced.  The increase shall prevail. For most of the tested varieties, a 2nm slit width can be used.