The microplate reader is actually a phase change photoelectric colorimeter or spectrophotometer, and its basic working principle is basically the same as the main structure and photoelectric colorimeter. The figure shows the working principle diagram of a single-channel automatic sampling microplate reader The light wave emitted by the light source lamp is transformed into a monochromatic light by the filter or monochromator, and enters the specimen under test in the plastic microporous pole. Part of the monochromatic light is absorbed by the specimen, and the other part is irradiated through the specimen. On the photodetector, the photodetector converts the different and different light signals of the specimen to be tested into corresponding electrical signals. The electrical signals are processed by preamplification, logarithmic amplification, analog-to-digital conversion and other signal processing and then sent to micro-processing The processor performs data processing and calculation, and finally displays the results by the display and printer. The microprocessor also controls the movement of the mechanical drive mechanism in the X direction and Y direction to move the microplate through the control circuit, so as to realize the automatic sampling detection process. The microplate reader is used to manually move the microplate for detection, so the mechanical drive mechanism and control circuit in the X and Y directions are omitted, so that the instrument is smaller and the structure is simpler.
A microplate is a transparent plastic plate that has been embedded in advance for placing the sample to be tested. There are rows of small holes of uniform size on the plate, and the corresponding antigen or antibody is embedded in the hole. Each small hole can hold a few tenths of a milliliter of solution.
Light is an electromagnetic wave. The wavelength of 100nm~400nm is called ultraviolet light, the light between 400nm and 780nm can be observed by the human eye, and the wavelength greater than 780nm is called infrared light. The reason why people can see colors is because the light hits the object and is reflected back by the object. Green plants are green because most plants absorb red-orange light and blue-violet light, but they do not absorb and reflect green, so plants appear green. The principle of microplate reader measurement is to detect the absorbance of the analyte at a specific wavelength.
With the development of detection methods, a single-unit desktop microplate reader with multiple detection modes is called a multifunctional microplate reader, which can detect absorbance (Abs), fluorescence intensity (FI), time-resolved fluorescence (TRF), and fluorescence polarization (FP). ), and chemiluminescence (Lum).
In principle, the microplate reader can be divided into a grating type microplate reader and a filter type microplate reader. The grating type microplate reader can intercept any wavelength within the wavelength range of the light source, while the filter type microplate reader can only intercept specific wavelengths for detection according to the optional filter.
