The calibration degree of any instrument is to enable it to work more accurately. UV spectrophotometer is an analytical instrument based on the principle of UV visible spectrophotometry, which uses the radiation absorption of substance molecules in the UV visible spectral region for analysis. Its calibration work must comply with certain specifications.

1. Before calibration, the UV spectrophotometer should be turned on and preheated for sufficient time to stabilize, usually at least 30 minutes later.

2. When selecting standard substances, it is necessary to pay attention to calibrating under the reproduction conditions of the standard values (i.e. the application conditions of the standard substance rules), otherwise incorrect calibration results may occur. For example, when using the GBW (E) 130066 spectrophotometer standard solution for calibration, it is necessary to meet two conditions:

a. The spectral bandwidth of the calibrated instrument should be 2nm. If the spectral bandwidth of the instrument cannot be adjusted and is greater than 2nm, the value given by the standard solution is not applicable and a corrected value should be used;

b. The two quartz colorimetric dishes selected for calibration should have an inner diameter of (10 ± 0.2) mm and good pairing at 235nm, 257nm, 313nm, and 350nm to reproduce the standard values.

3. When using standard solutions for calibration, it is also necessary to pay special attention to the laboratory temperature during calibration measurements, as these standard substances have different transmittance values at different temperatures.

4. It is necessary to store standardized substances under the specified conditions in the instruction manual. For example, interference filters should be kept in a dry and clean environment to avoid surface contamination, moisture, glue cracking, or mold growth. All standardized substances should be used within the validity period indicated on the certificate.

5. The uncertainty of the specification value of the neutral filter used in the UV spectrophotometer must comply with the transmission specification. During calibration, attention should be paid to standardizing the directionality of the filter.