Requirements for laser-induced desorption/ionization on submicrometer structures
Requirements for laser-induced desorption/ionization on submicrometer structures
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DOI：
10.1021/ac050504l
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发表时间：
2005-08-15
影响因子：
7.4
通讯作者：
Wada, Y
中科院分区：
文献类型：
--
作者：
Okuno, S;Arakawa, R;Wada, Y
研究了各种亚微米结构上的激光诱导和无基质解吸/电离。首先，为了检查表面粗糙度对电离的影响，用砂纸刮擦硅片或不锈钢。与相应的未处理表面相比，在划伤的不锈钢或硅上电离合成聚合物和利血平所需的 337 nm 氮激光的通量显着降低。接下来，在硅晶片上光刻制造的亚微米凹槽阵列产生了质子化血管紧张素，并且形态取向证明了激光和凹槽方向之间的正相关关系以促进电离。制造的结构还表明亚微米结构，而不是更小的结构，或纳米结构是粗糙表面上直接解吸/电离的关键因素。最后，当表面涂有金或铂时，氧化铝或聚乙烯的亚微米多孔结构响应直接紫外线照射，产生强烈的血管紧张素和胰岛素分子离子信号。该涂层还为多孔氧化铝芯片提供了延长活性的额外优势，即使将芯片放置在露天，也可以超过一个月。这些结果表明，无论基础材料如何，都可以在具有金或铂涂层表面的亚微米结构上实现有机化合物的激光诱导解吸/电离。
Laser-induced and matrix-free desorption/ionization on various submicrometer structures was investigated. First, to examine the effect of surface roughness on ionization, a silicon wafer or stainless steel was scratched with sandpaper. The fluences of a 337-nm nitrogen laser, required for ionization of synthetic polymers and reserpine, were markedly reduced on the scratched stainless steel or silicon as compared to the corresponding untreated surface. Next, arrays of submicrometer grooves, which had been lithographically fabricated on a silicon wafer, yielded protonated angiotensin, and the morphologic orientation demonstrated the positive relation between the laser and groove directions for promoting ionization. The fabricated structure also suggested the submicrometer, but not smaller, or nanometer, structures to be a key factor in direct desorption/ionization on rough surfaces. Finally, submicrometer porous structures of alumina or polyethylene yielded intense molecular ion signals of angiotensin and insulin, in response to direct UV irradiation, when the surface was coated with Au or Pt. The coating provided the additional advantage of prolonged activity for a porous alumina chip, exceeding a month even when the chip was left in the open air. These results indicate that laser-induced desorption/ionization of organic compounds can be implemented on submicrometer structures with an Au- or Pt-coated surface irrespective of the basal materials.