Absorbance Microplate Readers

Absorbance-based detection can be performed on the PHERAstar® FSX, CLARIOstar®, FLUOstar®, SPECTROstar® and POLARstar® Omega plate readers, as well as on the dedicated SPECTROstar Nano . A high-power xenon flash lamp illuminates the sample using a specific wavelength selected by an optical filter. In the case of most BMG LABTECH microplate readers, a UV/Vis spectrometer is used instead of filters to collect the entire spectrum instead of a specific wavelength. BMG LABTECH's spectrometer captures all wavelengths from 220 to 1000nm at a resolution of 1 – 10 nm in less than 1 second per well.

Absorbance microplate readers

Absorbance Overview


Absorbance, also known as Optical Density (OD), is defined as the (logarithmic) ratio between the intensity of light hitting a sample and the intensity of that very light transmitted through the sample. While a specific wavelength of light selected by a filter illuminates a sample, part of this light gets absorbed. The non-absorbed light passes through the sample and is collected by a detector located opposite the light source, on the other side of the microplate well.

Since the amount of light absorbed by a sample relates to its concentration (Lambert-Beer law), absorbance has been used for the quantification of nucleic acids and proteins as well as in popular colorimetric reactions such as ELISA tests. BMG LABTECH offers a variety of absorbance microplate readers.

Absorbance Products


The following plate readers can be configured to perform absorbance measurements:

PHERAstar FSX HTS plate reader CLARIOstar multi-mode plate reader SPECTROstar Nano absorbance plate reader Omega Series upgradeable plate readers
The new High-Throughput
Screening reader for fast
read times in all modes.
An advanced monochromator
reader for flexibility and
performance in all modes.
The dedicated absorbance
reader with UV-vis spectrometer
and additional cuvette port.
Upgradeable Omega Series
readers for absorbance or any
number of detection modes.

Absorbance Measurements


The following are examples of absorbance measurements takes on BMG LABTECH microplate readers:

See a complete list of absorbance application notes.