Karlinsey James M, Monahan Jennifer, Marchiarullo Daniel J, Ferrance Jerome P, Landers James P
Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, USA.
Anal Chem. 2005 Jun 1;77(11):3637-43. doi: 10.1021/ac048115z.
A recent report describes a reversible valve that can be used in series to achieve diaphragm pumping on chip (Grover, W. H.; Skelley, A. M.; Liu, C. N.; Lagally, E. T.; and Mathies, R. A. Sens. Actuators, B 2003, 89, 315-323). Here, the functionality of an integrated diaphragm pump on a hybrid PDMS-glass microchip to perform pressure injections for electrophoretic separations is demonstrated. A chip design that can perform both pressure and electrokinetic (EK) injection is described, and a mixture of fluorescein and ROX dyes in borate buffer is utilized as a model sample system. Multiple electrophoretic separations of sample injected with pressure and voltage are compared. Over multiple EK injections, an electrophoretic bias is observed and the injected analytes are not representative of the sample, with the peak area ratio changing 20% after 20 runs. Over multiple pressure injections, however, the sample composition is maintained, with a 3.6% CV over 20 runs. The data presented show the ability to alternate between injection types and pressure-inject a representative sample volume after a bias has already been observed with multiple EK injections. Multiple pressure injections have been performed on sample volumes as low as 500 nL while maintaining sample composition, supporting its use in integrated systems for small-volume sampling.
最近的一份报告描述了一种可逆阀，该阀可串联使用以实现芯片上的隔膜泵送（格罗弗，W.H.；斯凯利，A.M.；刘，C.N.；拉加利，E.T.；以及马西斯，R.A.《传感器与执行器，B辑》，2003年，89卷，315 - 323页）。在此，展示了一种集成在混合聚二甲基硅氧烷 - 玻璃微芯片上的隔膜泵的功能，该隔膜泵用于电泳分离的压力进样。描述了一种能够同时进行压力进样和电动（EK）进样的芯片设计，并使用硼酸盐缓冲液中的荧光素和ROX染料混合物作为模型样品系统。比较了通过压力和电压进样的样品的多次电泳分离。在多次EK进样过程中，观察到电泳偏差，且进样的分析物不能代表样品，20次运行后峰面积比变化了20%。然而，在多次压力进样过程中，样品组成得以保持，20次运行的变异系数为3.6%。所呈现的数据表明，在已经通过多次EK进样观察到偏差后，能够在进样类型之间切换并压力进样一个具有代表性的样品体积。已对低至500 nL的样品体积进行了多次压力进样，同时保持样品组成，这支持了其在小体积采样集成系统中的应用。
