A microplate reader is an optical device that can detect biological, chemical or physical processes or phenomena by measuring absorbance. Known by the name ELISA readers or Spectrophotometer s, they are associated with laboratory techniques used to determine antigens in samples.
The device works on the same physical principle as a UV-Vis Spectrophotometer : the amount of light transmitted or absorbed by a sample at different wavelengths. For this, it consists of a light source, a monochromator and a Detector.
Lighting system
In microplate readers, it is common to have a tungsten source for the visible region, although there are also devices on the market that can reach the UV range. Unlike conventional UV-Vis Spectrophotometer s, microplate readers typically work from 400nm to 700nm.
Detector
The Detector is responsible for converting the signal (photons) it receives into an electrical signal so that, depending on its intensity, it can be recorded by a system that provides absorbance or OD values.
Calibration of the Detector calibration involves determining the correctness of the absorbance value at a given wavelength and its uncertainty.
monochrome
Monochromators allow for the separation of spectra, providing beams of energy at specific wavelengths. In this way, it is possible to work at specific wavelengths. For example, if you are working with different compounds that have a characteristic absorbance at 690nm, you want your monochromator to accurately distinguish this wavelength from the others. It is necessary to ensure that the device works at 690nm and not 693nm.
If the wavelength is critical or affects the measurements being made, it is necessary to calibrate this part of the equipment, known as wavelength calibration.
A wavelength calibration checks the difference between the wavelength measured by the device and the wavelength of a reference standard used. Different wavelength points can be calibrated across the entire device range.
