Principle of Fluorescence Spectrophotometer

The instrument used to scan the fluorescence spectrum emitted by liquid-phase fluorescent markers is collectively referred to as a fluorescence spectrophotometer. It can provide various physical parameters, such as excitation spectrum, emission spectrum, fluorescence intensity, quantum yield, fluorescence lifetime, fluorescence polarization, etc., reflecting the bonding and structure of molecules from different perspectives. By measuring these parameters, the conformational changes of molecules in various environments can be inferred, and general quantitative analysis can also be conducted to elucidate the relationship between molecular structure and function.

The development of fluorescence spectrophotometers has gone through three stages:

1. Manual control of fluorescence spectrophotometer

2. Automatic recording fluorescence spectrophotometer

3. Computer-controlled fluorescence spectrophotometer

Fluorescence spectrophotometers can be divided into two series based on the number of beams: dual beam fluorescence spectrophotometers and single beam fluorescence spectrophotometers. Others are low-temperature laser Sh p ol‘ S technology fluorescence spectrophotometer, equipped with lifetime and phase resolution fluorescence spectrophotometer, etc.

The working principle of a fluorescence spectrophotometer is that the ultraviolet and blue violet light emitted by a high-pressure mercury lamp or xenon lamp is filtered through a filter and enters the sample cell, exciting the fluorescent substances in the sample to emit fluorescence. After filtering and reflection, the fluorescence is received by the photomultiplier tube and displayed in the form of graphics or graphs. Due to the different molecular structures, the distribution of excited state energy levels of different substances has different characteristics. This characteristic is reflected in fluorescence. Various substances have their unique fluorescence excitation and emission spectra, so different fluorescence excitation and emission spectra can be used for qualitative identification of substances.