What is the difference between a spectrometer and a monochromator for absorbance measurements?

October 29, 2012

A spectrometer incorporates a highly efficient optical grating and a solid state array detector that allows the measurement of light intensity throughout the entire UV and visible parts of the spectrum.

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Dr EJ Dell
PhD, Sales Manager Northwest

Similar to a monochromator, but much faster, the spectrometer allows you to capture the whole UV/Vis spectrum (220-1000 nm) of a sample within one second per well – no scanning is needed.


In practical terms, a monochromator only captures one measurement in the UV-Visible spectrum at a particular wavelength or a particular bandwidth, and therefore gives only one value. Whereas a spectrometer captures the entire UV-Visible spectrum in the same amount of time, giving values at every wavelength.


Here is a graphical representation of this – notice all of the information that is lost if a monochromator is used:


Find out more about this technology in an article on Genetic and Engineering News:

Microplate Reader Absorbance Assays - New Tools Bridge Gap between Single and Multiple Sample Absorbance Instruments.

For more information on the UV/Vis absorbance spectrometer technology used in BMG LABTECH's instruments, visit our website. BMG LABTECH instruments that have a spectrometer include: SPECTROstar Nano, Omega Series of readers, VANTAstar, CLARIOstar and the PHERAstar FSX.