Dh. Thomas et al., Selective trace enrichment by immunoaffinity capillary electrochromatography on-line with capillary zone electrophoresis - laser-induced fluorescence, ELECTROPHOR, 20(1), 1999, pp. 57-66
Limited by the lack of a sensitive, universal detector, many capillary-base
d liquid-phase separation techniques might benefit from techniques that ove
rcome modest concentration sensitivity by preconcentrating large injection
volumes. The work presented employs selective solid-phase extraction by imm
unoaffinity capillary electrochromatography (IACEC) to enhance detection li
mits. A model analyte, fluorescein isothiocyanate (FITC) biotin, is electro
kinetically applied to a capillary column packed with an immobilized anti-b
iotin-IgG support. After selective extraction by the immunoaffinity capilla
ry, the bound analyte is eluted, migrates by capillary zone electrophoresis
(CZE), and is detected by laser-induced fluorescence. The column is regene
rated and reused many times. We evaluate the performance of IACEC for selec
tive trace enrichment of analytes prior to CZE. The calibration curve for F
ITC-biotin bound versus application time is linear from 10 to 300 seconds.
Recovery of FITC-biotin spiked into a diluted urinary metabolites solution
was 89.4% Versus spiked buffer, with a precision of 1.8% relative standard
deviation (RSD).