title: White LEDs as broad spectrum light sources for spectrophotometry: demonstration in the visible spectrum range in a diode-array spectrophotometric detector.
abstract: 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.
authors.affiliation: Irish Separation Science Cluster, National Centre for Sensor Research and School of Chemical Sciences, Dublin City University, Dublin, Ireland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Piasecki
authors.forename: Michael C
authors.initials: MC
authors.lastname: Breadmore
authors.forename: Mirek
authors.initials: M
authors.lastname: Macka
mesh_terms: D003116:Color; D019075:Electrophoresis, Capillary; D008027:Light; D008904:Miniaturization; D010758:Phosphorus; D013053:Spectrophotometry / Q000295:instrumentation*
chemical_list: D010758:Phosphorus