Ultraviolet Spectrophotometer inspection

1. Inspection of wavelength accuracy

Use an interference filter or a praseodymium-neodymium filter to measure the absorption peak of the instrument. If the difference between the measured value and the standard value of the filter exceeds the regulations, wavelength adjustment is required.

2. Inspection of transmittance accuracy 

Use spectrally neutral filters with transmittance standard values ​​of about 10%, 20%, and 30% respectively, and measure the transmittance of each filter at the wavelengths of 440, 546, and 635nm in the visible light region, and air as a reference. In the ultraviolet region, use potassium dichromate solution at 235, 257, 313, and 350nm wavelengths respectively, and use perchloric acid solution as a reference to measure the transmittance. 

3. Test of stability

Under the condition that the zero point is not exposed to light, use the zero point regulator to adjust the instrument to zero point, and observe the change of the transmittance for 3 minutes, which is the zero point stability. 10nm from both ends of the measurement range of the instrument to the middle, after adjusting the zero point, cover the sample chamber cover (open the light door), let the photoelectric tube receive light, adjust the transmittance to 95% (adjust to 100% for the digital display instrument) and observe for 3 minutes Read the change of transmittance, which is the photocurrent stability.

4. Inspection of stray light

The visible spectrometer prism instrument is at 420nm, the grating instrument is at 360nm, and the ultraviolet spectrometer is at 220nm. Use cut-off filters that meet the regulations, and use air as a reference to measure the transmittance value, that is, the instrument at the corresponding wavelength. .