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White LEDs as broad spectrum light sources for spectrophotometry: Demonstration in the visible spectrum range in a diode‐array spectrophotometric detector
Author(s) -
Piasecki Tomasz,
Breadmore Michael C.,
Macka Mirek
Publication year - 2010
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201000341
Subject(s) - light emitting diode , optoelectronics , visible spectrum , optics , absorbance , spectrophotometry , detector , analytical chemistry (journal) , absorption spectroscopy , materials science , diode , chemistry , physics , chromatography
Although traditional lamps, such as deuterium lamps, are suitable for bench‐top instrumentation, their compatibility with the requirements of modern miniaturized instrumentation is limited. This study investigates the option of utilizing solid‐state light source technology, namely white LEDs, as a broad band spectrum source for spectrophotometry. Several white light LEDs of both RGB and white phosphorus have been characterized in terms of their emission spectra and energy output and a white phosphorus Luxeon LED was then chosen for demonstration as a light source for visible‐spectrum spectrophotometry conducted in CE. The Luxeon LED was fixed onto the base of a dismounted deuterium (D 2 ) lamp so that the light‐emitting spot was geometrically positioned exactly where the light‐emitting spot of the original D 2 lamp is placed. In this manner, the detector of a commercial CE instrument equipped with a DAD was not modified in any way. As the detector hardware and electronics remained the same, the change of the deuterium lamp for the Luxeon white LED allowed a direct comparison of their performances. Several anionic dyes as model analytes with absorption maxima between 450 and 600 nm were separated by CE in an electrolyte of 0.01 mol/L sodium tetraborate. The absorbance baseline noise as the key parameter was 5× lower for the white LED lamp, showing clearly superior performance to the deuterium lamp in the available, i.e. visible part of the spectrum.