ABSTRACT
Channels in microfluidic glass chips manufactured with the alternative powder blasting technology were permanently coated with poly(vinyl alcohol) (PVA) in order to improve the performance in microchip electrophoresis. The performance of coated and uncoated powder-blasted (pb) devices as well as coated and uncoated wet chemical etched (wc) chips was compared in electrophoretic separations of fluorescently labeled test compounds. The limited electrophoretic resolution obtained in pb-chips could significantly be improved by coating the channels with PVA. The resolution of test compounds in such coated pb-devices was even higher than in uncoated wc-chips. PVA-coated pb-chips could also successfully be applied in chiral separations. While in an uncoated pb-chip using a cyclodextrins buffer only one broad signal was obtained, two well-resolved signals were obtained in a coated device.
Subject(s)
Electrophoresis, Microchip/instrumentation , Glass , Microfluidic Analytical Techniques , Polyvinyl Alcohol/chemistry , Sensitivity and Specificity , StereoisomerismABSTRACT
Fast chiral separation of DNS-amino acids could be realized using microchip electrophoresis with fluorescence detection. For this purpose, highly sulfated cyclodextrins (HS-gamma-CD) were used as chiral selectors enabling high selectivity. Even subsecond separation of DNS-tryptophan, DNS-norleucine, DNS-phenylalanine, DNS-methionine, and DNS-aspartic acid could be achieved. Baseline separation could be accomplished within 720 ms, which is the fastest separation of enantiomers reported to date. A more complex mixture consisting of three chiral DNS-amino acids could be separated within 3.3 s utilizing a separation length of only 7 mm and an electrical field strength of 2012 V/cm.
