C. Eugene Bennet Department of Chemistry, West Virginia University, Morgantown, WV 26506, USA.
J Am Soc Mass Spectrom. 2011 Dec;22(12):2115-24. doi: 10.1007/s13361-011-0251-4. Epub 2011 Oct 12.
The performance of several electrospray ionization emitters with different orifice inside diameters (i.d.s), geometries, and materials are compared. The sample solution is delivered by pressure driven flow, and the electrospray ionization voltage and flow rate are varied systematically for each emitter investigated, while the signal intensity of a standard is measured. The emitters investigated include a series of emitters with a tapered outside diameters (o.d.) and unaltered i.d.s, a series of emitters with tapered o.d.s and i.d.s, an emitter with a monolithic frit and a tapered o.d., and an emitter fabricated from polypropylene. The results show that for the externally etched emitters, signal was nearly independent of i.d. and better ion utilization was achieved at lower flow rates. Furthermore, emitters with a 50 μm i.d. and an etched o.d. produced about 1.5 times more signal than etched emitters with smaller i.d.s and about 3.5 times more signal than emitters with tapered inner and outer dimensions. Additionally, the work presented here has important implications for applications in which maximizing signal intensity and reducing frictional resistance to flow are necessary. Overall, the work provides an initial assessment of the critical parameters that contribute to maximizing the signal for electrospray ionization sources interfaced with pressure driven flows.
比较了几种具有不同内径（ID）、几何形状和材料的电喷雾离子化发射器的性能。样品溶液通过压力驱动流输送，对每个研究的发射器系统地改变电喷雾电离电压和流速，同时测量标准物质的信号强度。所研究的发射器包括一系列具有锥形外径（OD）和不变 ID 的发射器、一系列具有锥形 OD 和 ID 的发射器、一个具有整体式 frit 和锥形 OD 的发射器以及一个由聚丙烯制成的发射器。结果表明，对于外部刻蚀的发射器，信号几乎与 ID 无关，并且在较低流速下实现了更好的离子利用率。此外，内径为 50 μm 的发射器和刻蚀 OD 的发射器产生的信号比具有较小 ID 的刻蚀发射器大约高 1.5 倍，比具有锥形内、外尺寸的发射器高约 3.5 倍。此外，这里介绍的工作对于需要最大化信号强度和降低流动摩擦阻力的应用具有重要意义。总的来说，这项工作初步评估了对与压力驱动流接口的电喷雾离子源最大化信号的关键参数。
