Study of an electroosmotic pump for liquid delivery and its application in capillary column liquid chromatography.
A packed-bed electroosmotic pump (EOP) was constructed and evaluated. The EOP consisted of three capillary columns packed in parallel, a gas-releasing device, Pt electrodes and a high-voltage power supply. The EOP could generate output pressure above 5.0 MPa and constant flow rate in the range of nl/min to a few microl/min for pure water, pure methanol, 2 mM potassium dihydrogenphosphate buffer, the buffer-methanol mixture and the pure water-methanol mixture at applied potentials less than 20 kV. The composition of solvent before/after pumping was quantitatively determined by using a gas chromatograph equipped with both flame ionization detector and thermal conductivity detector. It was found that there were no apparent changes in composition and relative concentrations after pumping process for a methanol-ethanol-acetonitrile mixture and a methanol-water mixture. Theoretical aspect of the EOP was discussed in detail. An capillary HPLC system consisting of the EOP, an injection valve, a 15 cm x 320 microm i.d., 5 microm Spherigel C18 stainless steel analytical column, and an on-column UV detector was connected to evaluate the performance of the EOP. A comparative study was also carried out with a mechanical capillary HPLC pump on the same system. The results demonstrated that the reproducibility of flow rate and the pulsation-free flow property of the EOP are superior to that of mechanical pump in capillary HPLC application.
Chen
Lingxin
L
Department of Analytical Chemistry and Micro-Instrumentation, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116012, China.
Ma
Jiping
J
Guan
Yafeng
Y
D000097:Acetonitriles; D000465:Algorithms; D002021:Buffers; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation*; D019075:Electrophoresis, Capillary / Q000295:instrumentation*; D000432:Methanol; D009995:Osmosis; D011312:Pressure; D015203:Reproducibility of Results; D012996:Solutions; D014867:Water
D000097:Acetonitriles; D002021:Buffers; D012996:Solutions; D014867:Water; D000432:Methanol