Chemically etched open tubular and monolithic emitters for nanoelectrospray ionization mass spectrometry
Chemically etched open tubular and monolithic emitters for nanoelectrospray ionization mass spectrometry
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DOI：
10.1021/ac061133r
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发表时间：
2006-11-15
影响因子：
7.4
通讯作者：
Smith, Richard D.
中科院分区：
文献类型：
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作者：
Kelly, Ryan T.;Page, Jason S.;Smith, Richard D.
我们已经开发了一种新的程序，用于制造电喷雾电离质谱（ESI-MS）的熔融石英发射器，其中裸露的熔融石英毛细管的末端浸入氢氟酸水溶液中，并通过毛细管泵送水以防止内部蚀刻。表面张力导致蚀刻剂爬上毛细管外部，并且所得弯月面中的蚀刻速率作为与本体溶液的距离的函数而降低。蚀刻继续进行，直到接触氢氟酸储存器的二氧化硅被完全去除，基本上停止蚀刻过程。由此产生的发射器没有内部锥度，使它们更不容易堵塞相比，e。例如，在一个实施例中，发射器发射器高的纵横比和极薄的壁在孔口有利于非常低的流速操作，稳定的ESI-MS信号，从5 μ m直径的发射器，在5 nL/min的流速与高度的intereptibility再现性模型分析物。在广泛的评估中，发现蚀刻发射器与传统的拉发射器相比，在失败之前能够对蛋白质组样品进行大约四倍的LC-MS分析。还采用制造过程来使含有聚合物整料的二氧化硅毛细管的端部逐渐变细以用作ESI发射器。与以前的工作相比，单片材料突出超过熔融二氧化硅毛细管，改善单片辅助电喷雾过程。
We have developed a new procedure for fabricating fused-silica emitters for electrospray ionization-mass spectrometry (ESI-MS) in which the end of a bare fused-silica capillary is immersed into aqueous hydrofluoric acid, and water is pumped through the capillary to prevent etching of the interior. Surface tension causes the etchant to climb the capillary exterior, and the etch rate in the resulting meniscus decreases as a function of distance from the bulk solution. Etching continues until the silica touching the hydrofluoric acid reservoir is completely removed, essentially stopping the etch process. The resulting emitters have no internal taper, making them much less prone to clogging compared to, e. g., pulled emitters. The high aspect ratios and extremely thin walls at the orifice facilitate very low flow rate operation; stable ESI-MS signals were obtained for model analytes from 5-mu m-diameter emitters at a flow rate of 5 nL/min with a high degree of interemitter reproducibility. In extensive evaluation, the etched emitters were found to enable approximately four times as many LC-MS analyses of proteomic samples before failing compared with conventional pulled emitters. The fabrication procedure was also employed to taper the ends of polymer monolith-containing silica capillaries for use as ESI emitters. In contrast to previous work, the monolithic material protrudes beyond the fused-silica capillaries, improving the monolith-assisted electrospray process.