Attomole amino acid determination by capillary zone electrophoresis with thermooptical absorbance detection

Abstract

Attomole quantities of 4-(dimethylamlno)azobenzene-4'sulfonyi chloride derivatlzed amino acids are separated by using capillary zone electrophoresis In a mixed acetonitrile/ aqueous buffer system. Detection Is performed with an oncolumn thermooptical absorbance detection technique based on a 130-mW argon Ion pump laser. Detection limits for the concentration of analyte Injected onto the column range from 5 X 10"® M for methionine to 5 X 10"7 M for aspartic acid. Only 37 a mol of methionine and 450 amol of aspartic acid are

An interface chip connection between capillary electrophoresis and thermal lens microscope

“…3) as reported previously [31]. By adopting the interface chip, optical alignment for reproducible detection became easier than that in direct detection methods like the previous methods [29,30].…”

“…Dovichi and co-workers [29,30] developed a thermooptical absorbance detection system for CE. Although the system had very good sensitivity and applicability, optical alignment of the setup seemed very difficult and it may be hard to realize reproducible determinations, because two laser beams must be focused in a solution filled in a narrow capillary tube with a curved surface.…”

Recent advances in the isolation and structural studies of biomacromolecules using microcolumn techniques

“…Using elaborate instrumental techniques, Dovichi and coworkers have shown the most impressive detection limits in the analysis of standard amino acids (40,41). With the crossbeam thermooptical absorbance detection of the 4-(dimethy1amino)azobenzene-4' -sulfonyl (DABSYL) derivatives (40), detection limits at attomole levels were indicated.…”

“…With the crossbeam thermooptical absorbance detection of the 4-(dimethy1amino)azobenzene-4' -sulfonyl (DABSYL) derivatives (40), detection limits at attomole levels were indicated. Following a reaction with fluorescein isothiocyanate, detection of 6000 molecules has been accomplished through the use of a sheath-flow optical microcell illuminated by an argon-ion laser beam (41).…”

Highly Sensitive and Direct Detection of DNA Fragments Using a Laser-Induced Capillary Vibration Effect

“…Moreover, because the photothermal signal is proportional to excitation beam power, the sensitivity is as high as that of laser-induced fluorometry when using an intense light source, such as a laser, as the excitation beam. We and other research groups have proposed and developed photothermal detection techniques -thermooptical detection, [5][6][7][8][9] laser-induced capillary vibration (CVL) detection, [10][11][12][13][14][15] etc. -as highly sensitive and direct (no labeling) detection methods of capillary electrophoresis (CE).…”