Sensitive analysis of [D-Pen2,5]enkephalin in rat serum by capillary electrophoresis and laser-induced fluorescence detection.
A highly sensitive analytical method based on capillary zone electrophoresis (CZE) coupled with a laser-induced fluorescence (LIF) detector was explored for the analysis of [D-Pen2,5]enkephalin (DPDPE) in rat serum. DPDPE and the internal standard Phe-Leu-Glu-Glu-Ile (P9396) were extracted from serum samples with C18 solid-phase extraction disk cartridges, followed by derivatization with tetramethylrhodamine-5-isothiocyanate (TRITC) isomer G before introduction onto the capillary column. Complete resolution of DPDPE and the internal standard from other serum components was achieved within 20 min on a 140 cm x 50 microns I.D. capillary column with borate buffer (25 mM. pH 8.3). With the current method, it is possible to detect 1.3E-18 mol of DPDPE on column. The results suggest that CZE-LIF is a promising method for the sensitive and specific quantitation of therapeutic peptides in biological matrices.
Chen
C
C
Division of Pharmaceutics, School of Pharmacy, University of North Carolina at Chapel Hill 27599, USA.
Jeffery
D
D
Jorgenson
J W
JW
Moseley
M A
MA
Pollack
G M
GM
D000818:Animals; D019075:Electrophoresis, Capillary; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000097:blood*; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D007834:Lasers; D013058:Mass Spectrometry; D051381:Rats; D017465:Receptors, Opioid, delta / Q000819:agonists*; D012235:Rhodamines; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence
D004745:Enkephalins; D005456:Fluorescent Dyes; D017465:Receptors, Opioid, delta; D012235:Rhodamines; C009434:tetramethylrhodamine isothiocyanate; D020881:Enkephalin, D-Penicillamine (2,5)-