title: [A novel method for the direct measurement of electroosmotic flow velocity on microfluidic chips].
abstract: As microfluidic technologies mature, accurate methods for the measurement of electroosmotic flow velocity on microfluidic chips are becoming increasingly important. A change of migration time of Rhodamine 123 (Rh123) at different pH values of the buffer was observed during the electrophoresis, and it was deduced that there is uncharged molecular form of Rh123 in alkaline solution because of deprotonation. Therefore, a method of direct measurement of electroosmotic flow velocity on microfluidic chip was developed based on the detection of migration time of the uncharged Rh123, because the migration speed of uncharged molecule is equal to the electroosmotic flow velocity. The electroosmotic flow velocity of glass microchip at pH 9.3 and 10.1 of the buffer was detected to be 3.9 x 10(-4) cm2/(s V) and 4.1 x 10(-4) cm2/(s V), respectively, which were in agreement with those obtained by the traditional method.
authors.affiliation: College of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou 510006, China. sunyue1102@yahoo.com.cn
authors.forename: Yue
authors.initials: Y
authors.lastname: Sun
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Shen
authors.forename: Changqing
authors.initials: C
authors.lastname: Zeng
mesh_terms: D053841:Electroosmosis / Q000379:methods*; D046209:Electrophoresis, Microchip / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D020112:Rhodamine 123 / Q000737:chemistry
chemical_list: D020112:Rhodamine 123