The error of ultraviolet spectrophotometer is a key issue. If there is an error in the spectrophotometer, the measured values will also vary greatly, which has a significant impact on the research project. Therefore, attention should be paid to the error. So how do we correct the photometer to avoid errors? Let's take a look together.

The important physical and chemical quantity of UV spectrophotometry is absorbance. In order to obtain accurate research results, it is very important to accurately measure the absorbance of sample solutions. Usually, the unreliability of analysis results is related to both accidental and systematic errors. Accidental errors can affect the accuracy of measurements, and this error can be reduced through sufficient statistical processing; Systematic errors affect the accuracy of measurement results, and these errors can be unified by comparing the accurate measurement results of substances under roughly the same experimental conditions.

The effects of systematic errors (wavelength correction, slow astigmatism of the spectrophotometer, linear response of the amplifier, dark current, and optical path of the cuvette) and operational errors (temperature changes, instrument readings, operator changes, purity of the substance used, weighing and concentration, pH) can be examined and calibrated for UV spectrophotometers. In most cases, by strictly following the operating procedures, adjusting the instrument to zero and accurately weighing it, operational errors can be controlled or reduced. Regular calibration of a spectrophotometer can overcome the system errors of the instrument. If high-precision measurement is required, it must be calibrated daily. The specific calibration content is as follows:

1. The error between the wavelength value displayed by the instrument for wavelength accuracy testing and the actual wavelength value of monochromatic light should be within ± 1.0nm. Calibration can be performed using the 486.02nm and 656.10nm spectral lines of the deuterium lamp in the instrument;

2. Absorbance accuracy test;

3. Stray light testing;

4. Wavelength reproducibility test;

5. Resolution testing.