Automated Particle Electrophoresis: Modeling and Control of Adverse Chamber Surface Properties
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- 作者：Robert J. Knox ; Norman L. Burns ; James M. Van Alstine ; J. Milton Harris ; and Geoffrey V. F. Seaman
- 刊名：Analytical Chemistry
- 出版年：1998
- 出版时间：June 1, 1998
- 年：1998
- 卷：70
- 期：11
- 页码：2268 - 2279
- 全文大小：129K
- 年卷期：v.70,no.11(June 1, 1998)
- ISSN：1520-6882
文摘
Electrophoretic analysis of colloidal particles isadverselyaffected by a host of surface phenomena, including electroosmosis, phase wall wetting, and sample or air bubbleadsorption. Neutral, hydrophilic polymer coatingscontrolsuch phenomena on a variety of surfaces.Poly(ethyleneglycol)-poly(ethylene imine) (PEG-PEI) conjugatessignificantly reduce electroosmosis and positively controladsorption and wetting in the glass sample chambers (5mm × 3 mm × 1 mm i.d.) employed in a representativecommercial electrophoresis apparatus (Coulter DELSA440). The reduction in electroosmosis (e.g., 80% in7.5mM solution at pH 11) was similar to that exhibited bycoated 2-mm-i.d. quartz capillaries in a Rank MK Imanual apparatus. PEG-PEI coatings significantly reduce electroosmosis over a wide range of pH (2-11) andionic strength (1-100 mM) and can be stable for weeksunder normal laboratory conditions. They greatly enhance ease of operation and accuracy (sample meanelectrophoretic mobility ± SD) of the DELSA 440.Thelatter results from reduced electroosmosis flow profilegradients near the chamber center-axis stationary levels,where particle mobility is typically measured. Suchflowprofiles may also be affected by chamber wall surfaceasymmetries. A hydrodynamic description of electroosmotic fluid flow in rectangular chambers was adapted inorder to analyze the propagation of errors due to bothnonideal focusing and chamber surface asymmetry. Theanalysis indicated that the accuracy of rectangular chambered devices may be improved by measuring particlemobility at stationary levels different than chambercenter-axes. As a result, some rectangular chambers mayconferaccuracy advantages over cylindrical chambers.