Microplate Reader

A Microplate Reader, commonly called as plate reader or plate spectrophotometer, is an analytical instrument that reads or detects the physical, chemical, and biological events of the analyte, within the wells of the plate. It has numerous tiny wells where the sample analyte is introduced for analysis.

A standard spectrophotometer measures the absorbance of one sample at a time. The sample is typically placed in a cuvette through which light is sent horizontally. An absorbance plate reader offers higher throughput and can measure the absorbance of samples in microplates (typically 96-well or even 384-well) by sending light through each well vertically.

Microplate-based measurements detect light signals produced by a sample, converted by a sample, or transmitted through a sample. In the plate reader, the signal is measured by a detector, usually a photomultiplier tube (PMT). PMTs convert photons into electricity that is then quantified by the microplate reader. The output of this process is numbers by which a sample is quantified.

Tungsten-halogen or xenon flash lamps are generally used. LEDs have also come into the picture in some modern readers.

The detection technology can be of 3 types- Monochromator based detection which provides flexibility, convenience, and spectral scanning; Filter based detection which enables rapid switch between different wavelengths; Hybrid detection which has dual technological advantage of both flexibility and sensitivity.