Lin Chun-Che, Lee Gwo-Bin, Chen Shu-Hui
Department of Chemistry, National Cheng Kung University, No. 1 Ta-Hsueh Road, Tainan 701, Taiwan.
Electrophoresis. 2002 Oct;23(20):3550-7. doi: 10.1002/1522-2683(200210)23:20<3550::AID-ELPS3550>3.0.CO;2-A.
Automation of electrophoretic microchips for sequential analysis of different samples is demonstrated. This system used an autosampler, which was on-line connected to the microchip and the whole process including sample loading and injection, analysis and data acquisition as well as washing were all automated. Rhodamin B at different concentrations was first loaded into a hydrodynamic flow stream by an autosampler, delivered to the microchip, and then sequentially injected into the electrophoretic microchannel for analysis and detection. Automation was achieved by running two independent programs, one for sample loading by an autosampler and the other one for electrophoretic injection by voltage switching, on the same computer. Using this sampling chip, each loaded volume (0.2-1 microL) can be injected for dozens of electrophoretic analyses (1-10 nL for each injection). The variances caused by the external connections, which did not affect the electrophoretic analysis but would cause band broadening of the loaded sample in the hydrodynamic flow stream, were theoretically deduced. Results indicate that the dead volume (approximately 300 nL) due to the connection fitting on the chip could lead to dilution of the loaded sample by a factor of one when 0.2 microL of sample was loaded. Such a design allows sequential analysis of a series of samples while the running buffer is continuously pumped into the connection capillary as well as microchannels for washing between two loaded samples to minimize cross contamination without human intervention. Using this sampling chip, the required sample amount and handling time can be greatly reduced compared to the manual method.
展示了用于不同样品顺序分析的电泳微芯片自动化。该系统使用了一个自动进样器，它在线连接到微芯片，整个过程包括样品加载和进样、分析和数据采集以及清洗均实现自动化。不同浓度的罗丹明B首先由自动进样器加载到流体动力流中，输送到微芯片，然后顺序注入电泳微通道进行分析和检测。通过在同一台计算机上运行两个独立程序实现自动化，一个程序用于通过自动进样器加载样品，另一个程序用于通过电压切换进行电泳进样。使用这种进样芯片，每次加载的体积（0.2 - 1微升）可用于数十次电泳分析（每次进样1 - 10纳升）。理论推导了由外部连接引起的方差，其虽不影响电泳分析，但会导致流体动力流中加载样品的谱带展宽。结果表明，当加载0.2微升样品时，芯片上连接配件导致的死体积（约300纳升）会使加载样品稀释一倍。这种设计允许在运行缓冲液连续泵入微通道和连接毛细管，以便在两次加载样品之间进行清洗以最大程度减少交叉污染且无需人工干预的情况下对一系列样品进行顺序分析。与手动方法相比，使用这种进样芯片可大大减少所需样品量和操作时间。
