<title>Ultratrace analysis of biological substances by capillary electrophoresis/semiconductor laser fluorometry</title>

Abstract

Iii order to simplify a laser fluorometric detector for capillary electrophoresis, a semiconductor laser emitting at 660 nm is used as an exciting source. A labeling reagent fluorescent in the deep-red region is newly synthesized and used for determination of amino acids. The separation resolution is several hundred thousand and the detection limit is subattomole levels. Protein is also labeled by the dye developed and is measured at subfemtomole levels. Contrarily, nonfluorescent samples are detected by indirect fluorometry. Amino acids, flavin adenine dinucleotide (FAD) and deoxyadenosine monophosphate (dAMP) are determiiied, the detection limit being subpicomole levels.

Capillary Electrophoresis

“…Semiconductor lasers have the advantage of lower cost, smaller size, and a longer lifetime when compared to the more traditional laser sources. Semiconductor lasers which provide excitation in the blue (frequency doubled) (), the visible (), and the deep-red regions were described ( − ). In particular, Mank and Yeung recently utilized the red-absorbing label dicarbocyanine to detect amino acids at a detection limit on the order of 0.1 amol (1 amol = 10 -18 mol) ().…”