title: Absorbance detector for capillary electrophoresis based on light-emitting diodes and photodiodes for the deep-ultraviolet range.
abstract: A new absorbance detector for capillary electrophoresis featuring relatively high intensity light-emitting diodes as radiation sources and photodiodes for the deep-UV range was developed. The direct relationship of absorbance values and concentrations was obtained by emulating Lambert-Beer's law with the application of a beam splitter to obtain a reference signal and a log-ratio amplifier circuitry. The performance of the cell was investigated at 255 nm with the detection of sulfanilic, 4-nitrobenzoic, 4-hydroxybenzoic and 4-aminobenzoic acid and the indirect detection of acetate, propionate, butyrate and caproate using benzoate as the displacement dye molecule. Vanillic acid, L-tyrosine and DL-tryptophan as well as the sulfonamides sulfamerazine, sulfathiazole and sulfamethazine were determined at 280 nm. Good linearities over 3 orders of magnitude were obtained. The noise level recorded was as low as 50 μAU and the drift typically <200 μAU/5 min.
authors.affiliation: Department of Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel, Switzerland.
authors.forename: Duy Anh
authors.initials: DA
authors.lastname: Bui
authors.affiliation: Department of Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel, Switzerland. Electronic address: Peter.Hauser@unibas.ch.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Hauser
mesh_terms: D002264:Carboxylic Acids / Q000032:analysis; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods; D013425:Sulfanilic Acids / Q000032:analysis; D013449:Sulfonamides / Q000032:analysis; D014364:Tryptophan / Q000032:analysis; D014443:Tyrosine / Q000032:analysis; D014466:Ultraviolet Rays
chemical_list: D002264:Carboxylic Acids; D013425:Sulfanilic Acids; D013449:Sulfonamides; D014443:Tyrosine; D014364:Tryptophan
keywords: Capillary electrophoresis; Deep-UV LED; Photodiode