Hoffmann Peter, Eschner Markus, Fritzsche Stefanie, Belder Detlev
University of Leipzig, Institute of Analytical Chemistry, Johannisallee 29, 04103 Leipzig, Germany.
Anal Chem. 2009 Sep 1;81(17):7256-61. doi: 10.1021/ac9015038.
The performance of microfluidic glass devices with a monolithically integrated nanospray tip have been evaluated. The nanospray tip is generated directly on the edge of a microfluidic glass chip by a pulling step followed by HF-etching for directed formation of a sharp tip with defined emitter area. For a fair judgment of the MS-detection sensitivity, we compared the detection performance with commercial nanospray needles. For that purpose the effect of the emitter opening on the sensitivity was studied in detail for different microfluidic chips as well as for commercial nanospray needles. A comparison of the chip-nanospray device with commercial nanospray needles revealed that a comparable spray performance is obtained at similar emitter diameters. A stable electrospray could be generated at such tapered tips without any need for hydrodynamic or electroosmotic pumping. The nanospray chips were successfully applied for coupling microchip electrophoresis and mass spectrometry. For improved performance, the separation channel of the microdevice was flushed with hydroxypropylmethylcellulose (HPMC) in order to reduce analyte-wall interactions and electroosmotic flow.
对具有整体集成纳米喷雾尖端的微流控玻璃器件的性能进行了评估。通过拉伸步骤，然后进行HF蚀刻以定向形成具有确定发射极面积的尖锐尖端，直接在微流控玻璃芯片的边缘生成纳米喷雾尖端。为了公平判断质谱检测灵敏度，我们将检测性能与商用纳米喷雾针进行了比较。为此，针对不同的微流控芯片以及商用纳米喷雾针，详细研究了发射极开口对灵敏度的影响。将芯片纳米喷雾装置与商用纳米喷雾针进行比较发现，在相似的发射极直径下可获得相当的喷雾性能。在这种锥形尖端处可以产生稳定的电喷雾，而无需任何流体动力或电渗泵。纳米喷雾芯片已成功应用于微芯片电泳和质谱联用。为了提高性能，用羟丙基甲基纤维素（HPMC）冲洗微器件的分离通道，以减少分析物与壁的相互作用和电渗流。
