Schnelle chirale Trennungen in mikrofluidischen Strukturen

A modular instrument for high-speed microchip electrophoresis (MCE), equipped with
a sensitive, variable wavelength fluorescence detection system, was developed and
evaluated. The system was applied to achiral separations of fluorescein
isothiocyanate (FITC)-labeled amines as well as for achiral separation of rhodamines
At optimised conditions baseline separation of four FITC-labeled amines could be
obtained in less than 50 s at a detection limit of 460 ppt (1 pM). Three rhodamines
could be baseline-separated in less than 6 s at a detection limit of 240 ppt (500 pM).
For demanding chiral separations of FITC-labeled amines the low resolution has to
be improved. For this the channels of microfluidic glass chips have been coated with
poly(vinyl alcohol) (PVA). Baseline separation of the enantiomers could be achieved
in coated devices while it was not possible in uncoated chips. The high resolution
enabled determination of small enantiomeric impurities with high precision (RSD=1.9
%) and trueness (R=0.9996). Applying a MCE-system with UV-detection chiral
separations of numerous unlabeled drugs could be realised in less than a minute.
The fastest separation could be performed in 2.5 s. Even the successful separation
of a mixture of three chiral drugs could be performed in a single run in less than 11 s
utilizing a separation length of only 12 mm.