Electrophoresis, Vol.30, No.13, 2300-2306, 2009
Assay of bradykinin metabolites in human body fluids by CE-LIF coupled with transient ITP preconcentration
A CE with LIF detection was developed for the separation and determination of three bradykinin (BK) metabolites: BK2-9, BK1-7 and BK1-5. BK fragments were derivatized with 5-(4, 6-dichloro-s-triazin-2-ylamino) fluorescein before CE-LIF analysis. Eighty millimolar of Tris-H3PO4 (pH 9.0) was selected as the derivatization media. Three BK fragments were baseline separated within 10 min by using 0.2 M TAPS-Tris buffer (pH 8.5) as the running buffer. Meanwhile we have also developed a simple, quick, and sensitive on-column transient ITP preconcentration for CE-LIF detection of three BK fragments. Ten millimolar of Tris-HCl (pH 9.0) was chosen as the leading electrolyte and 0.2 M TAPS-Tris (pH 8.5) containing 10 mM 1-butyl-3-methylimidazolium tetrafluoroborate as the terminating electrolyte and also served as the running buffer during CZE separation. By using this transient ITP coupled with CE-LIF, concentration detection limits (S/N= 3) for BK2-9, BK1-7 and BK1-5 were 0.3, 0.1 and 0.1 pmol/L, respectively. This method has been applied to the assay of human saliva and plasma samples with satisfactory results.