Popularity：586 Published Date：2022-01-06 13:04
What is Stokes Shift?
After being excited by light, the electrons of the substance will interact with the surrounding atoms before returning from the excited state to the ground state to cause a part of the excitation energy to move in other forms such as heat, which is not radiation, and cause deactivation, resulting in energy difference. This energy difference between the excitation light and the luminescence is called the Stoke Shift.
If the Stokes shift is smaller, the corresponding interference of the excitation spectrum will be greater when the emission part is detected, which will affect the detection sensitivity.
Why use TRF?
When doing fluorescence measurement, due to the interference of the background fluorescence signal, the traditional fluorescent dyes are susceptible to the interference of autofluorescence when detecting, which causes a serious decrease in sensitivity. At the same time, the lifespan of the traditional fluorescent dyes is relatively short.
Since most of the background fluorescence signal exists for a short time, the use of long-decay-life markers can minimize transient fluorescence interference.
Technical Principle of TRF
1. TRF uses special lanthanide elements as dyes (Europium, Samarium and Terbium)
The fluorescence lifetime can reach μs level after being excited, even up to 2ms (the fluorescence lifetime of ordinary fluorescein is ns level)
2. TRF markers are excited by very short light pulses
The excitation light must be turned off for a very short time
Measurement of emission after the excitation light is extinguished
Advantages of TRF
After the excitation is turned off, the emission can be continuously expressed or released to avoid the interference of excitation light during detection.
The Stoke shift of lanthanides is very wide, generally between 200-300μm, which can avoid interference between the two types of light.
TRF has high sensitivity, strong specificity, good stability, simple preparation of markers, good detection repeatability, and short operation process. It is suitable for ultra-micro analysis in biology and medicine, such as hormone detection and viral hepatitis marker detection. , Targeted cell label detection and drug screening.
ALLSHENG Multi-Mode Microplate Reader Feyond-A400 is based on Feyond-A300 with time-resolved fluorescence function. Time-resolved fluorescence means that after the excitation light is turned off, the emitted light can be continuously expressed or released to avoid interference from the excitation light during detection. Time-resolved fluorescence has high sensitivity, strong specificity, good stability, and short operation flow. It is suitable for ultra-micro analysis in biology and medicine, such as hormone detection, viral hepatitis marker detection, target cell marker detection, and drug screening.