Stenken J A, Topp E M, Southard M Z, Lunte C E
Department of Chemistry, University of Kansas, Lawrence 66045.
Anal Chem. 1993 Sep 1;65(17):2324-8. doi: 10.1021/ac00065a026.
The use of microdialysis sampling was examined in a well-characterized hydrodynamic system. A cross-flow microdialysis probe was designed in which the flow of both the dialysis perfusion solution and the sample solution could be carefully controlled. Dialysis membranes of cellulose (Cuprophan), cellulose acetate, and polyacrylonitrile (PAN) were examined in this system using hydroquinone as the test analyte. The permeability of the membranes to hydroquinone ranged from 1.72 x 10(-6) cm2/s for PAN to 2.97 x 10(-7) cm2/s for cellulose acetate. Determination of the dialysis fibers' recovery as a function of the sample flow velocity resulted in a rapid increase in recovery with increase in flow velocity. The recovery plateaued at high sample velocity. These results show that at low sample velocity diffusion through the sample solution is the rate-limiting step in recovery while at higher velocity transport through the membrane becomes rate limiting. Recovery for all three membrane types plateaued above sample velocities of 0.211 cm/s. This is well below the velocity of most biological fluids in which microdialysis sampling has been applied. This result supports previous reports that an in vitro calibration of microdialysis probes is appropriate for use in hydrodynamic environments in vivo such as the blood and bile.
在一个特性明确的流体动力学系统中对微透析采样的应用进行了研究。设计了一种错流微透析探头，其中透析灌注液和样品溶液的流动均可得到精确控制。在该系统中，以对苯二酚作为测试分析物，对纤维素（铜氨丝）、醋酸纤维素和聚丙烯腈（PAN）的透析膜进行了检测。这些膜对对苯二酚的渗透率范围为：PAN为1.72×10⁻⁶ cm²/s，醋酸纤维素为2.97×10⁻⁷ cm²/s。将透析纤维的回收率测定为样品流速的函数，结果显示回收率随流速增加而迅速上升。在高样品流速下回收率趋于平稳。这些结果表明，在低样品流速时，通过样品溶液的扩散是回收率的限速步骤，而在较高流速时，通过膜的传输成为限速步骤。所有三种膜类型的回收率在样品流速高于0.211 cm/s时趋于平稳。这远低于大多数应用微透析采样的生物流体的流速。该结果支持了先前的报道，即微透析探头的体外校准适用于体内流体动力学环境，如血液和胆汁。
