What Factors Should We Consider When Choosing A UV Spectrophotometer?

Technical Knowledge 2024-01-03 10:51:58
UV spectrophotometers are widely used in organic chemistry research. It is usually used for substance identification, purity inspection, and research on organic molecular structure. In terms of quantification, it can determine the content of each component in compounds and mixtures with complex structures. It can also determine the dissociation constant of substances, the stability constant of complexes, indicate the end point in molecular weight identification and microtitration of substances, and indicate the end point in high-performance liquid chromatography. For detectors, etc.

Choice UV spectrophotometer:

     When we choose various instruments, we have certain standards, such as measurement accuracy or measurement range. When selecting a UV spectrophotometer, we consider optical construction, spectral range, sample type, and analytical tools.

     The optical structure mainly refers to whether the light given by the UV spectrophotometer is a single beam or a double beam. Single beam measurement uses a single beam of light. The wavelength is given during the measurement process, and then the absorbance results are obtained through the measured object and the control object. The double beam splits the beam into two parts through a light-cutting wheel.

     Light sources include infrared, ultraviolet and visible light. Tungsten lamps and halogen lamps generally only cover the visible part of the light. The xenon lamp can cover the ultraviolet and visible light regions.

     UV spectrophotometers typically use photomultiplier tubes and photodiodes to measure absorbance.

     UV spectrophotometers accept sample wells, cuvettes, pipettes, and microplates for most sample types.

     Most stand-alone UV spectrophotometers include software to drive the instrument and manage data. High-performance instruments, usually used with a PC, require additional software from the manufacturer. Users can also choose to upgrade the software to meet their needs.

The basic working principle of UV spectrophotometer:

     The UV spectrophotometer uses ultraviolet-visible light of a certain frequency to illuminate the organic substance being analyzed, causing the transition of valence electrons in the molecule, which will be selectively absorbed. A set of spectra whose absorption changes with wavelength, reflecting the characteristics of the specimen. In the range of ultraviolet and visible light, for a specific wavelength, the degree of absorption is proportional to the concentration of the component in the sample. Therefore, the measured spectrum can be used for qualitative analysis, and based on the comparison of the absorption with a standard sample of known concentration, it can also be carried out. Quantitative analysis.

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