In part I of the Evolution of ICP, we focused on the first decade of ICP instruments, which were based on the Paschen-Rünge optical design. In part II of the blog series, we jump into the 1980s, and the next era in innovation.
The wavelength restrictions associated with the Paschen-Rünge optical design led to the development of sequential spectrometers in the early 1980s. Most of these instruments relied on the principle of scanning a dispersive optic (typically a ruled or holographic diffraction grating) to select the specific wavelength of light corresponding to the element of interest. These instruments were extremely versatile, possessing the ability to access nearly any wavelength in the electromagnetic spectrum from 160 - 900 nm. Their downside lay in their ability to access only one wavelength at a time (thus named sequential), resulting in slow analysis times. On an instrument of this type, a typical analysis could take several minutes to cover the 10 to 20 elements of interest. A schematic diagram of a typical scanning sequential spectrometer is shown in the schematic below:Read More