UV spectrophotometers are widely used in organic chemistry research. Usually used for substance identification, purity check, and research of organic molecular structure. In terms of quantification, the content of each component in compounds and mixtures with complex structures can be determined. It can also measure the dissociation constant of the substance, the stability constant of the complex, the molecular weight identification of the substance and the indication end point in the microtitration and as a detector in the high performance liquid chromatography.
Choice of UV Spectrophotometer:
When we choose various instruments, there are certain criteria, such as measurement accuracy, or measurement range. When choosing 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 is measured by 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 is divided into two by a chopper wheel.
Light sources include infrared, ultraviolet and visible light. Tungsten and halogen lamps generally cover only the visible light portion. The xenon lamp can cover the ultraviolet and visible light regions.
UV vis spectrophotometers typically use photomultiplier tubes and photodiodes to measure absorbance.
The UV spectrophotometer accepts sample wells, cuvettes, pipettes, and microplates for most sample types.
Most stand-alone UV spectrophotometers include software that drives the instrument and manages data. High-performance instruments, usually used in conjunction with a PC, require additional software from the manufacturer. At the same time users can also choose to upgrade the software to meet their needs.
The basic working principle of UV spectrophotometer:
The UV spectrophotometer utilizes a certain frequency of UV-visible light to irradiate the analyzed organic substance, causing the transition of valence electrons in the molecule, which will be selectively absorbed. A set of spectra whose absorption varies with wavelength, reflecting the characteristics of the sample. 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, so the measured spectrum can be qualitatively analyzed, and based on the comparison of the absorption with a standard sample of known concentration, it can also be Quantitative analysis.