Wavelength Calibration

ICP-OES is a powerful elemental analysis technique which utilizes the UV/Visible spectrum (typically 165 to 800nm) to measure emission from most elements in the periodic table. When configured correctly, today’s instruments yield detection limits of 1 to 10 ppb for the majority of elements.

What is Wavelength Calibration?

Minute variations in diffraction gratings cause every ICP-OES instrument to have a unique correlation between emission wavelengths and where each wavelength falls on the instrument’s array detector. Wavelength calibration is the process whereby that correlation is established and then stored in the instrument’s software for use during subsequent analytical measurements. It is the process used to “teach” the instrument exactly which pixels of its array detector correspond to each emission wavelength.

Why is Wavelength Calibration Important?

The presence or absence of emission lines is used for qualitative identification of each element, whereas emission intensity is used for quantification. Wavelength calibration helps the instrument and analyst ensure that they are measuring each element at the proper location in the spectrum. Below we will see how wavelength calibration impacts virtually every aspect of your ICP’s performance, including its sensitivity (detection limits), stability (RSDs), and susceptibility to interferences.