Characterization of digoxigenin-labeled B-phycoerythrin by capillary electrophoresis with laser-induced fluorescence. Application to homogeneous digoxin immunoassay.
A laser-induced fluorescence (LIF) immunoassay technique based on capillary electrophoretic (CE) separation is demonstrated. The analysis of digoxin in serum at clinically useful concentration levels of 10(-9) to 10(-10) M is achieved using this technique. The chemistry presented here using digoxigenin-labeled B-phycoerythrin was selected as a convenient model for the exploration of CE-LIF-based immunoassays. The LIF system described here exhibits detection limits in the low 10(-11) M range for several common fluorophores. The data presented in this report are one of the first examples of nanomolar quantitative analysis in a human serum matrix by CE.
Chen
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Beckman Instruments Inc., Fullerton, CA 92634.
Pentoney
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SL
D001667:Binding, Competitive; D002197:Capillary Action; D004076:Digoxigenin; D004077:Digoxin / Q000097:blood*; D004586:Electrophoresis / Q000379:methods*; D005453:Fluorescence; D005456:Fluorescent Dyes; D006801:Humans; D007118:Immunoassay; D007834:Lasers; D010799:Phycoerythrin / Q000737:chemistry / Q000302:isolation & purification*
D005456:Fluorescent Dyes; D010799:Phycoerythrin; D004077:Digoxin; D004076:Digoxigenin