Source of heavy molecular ions based on Taylor cones of ionic liquids operating in the pure ion evaporation regime
Source of heavy molecular ions based on Taylor cones of ionic liquids operating in the pure ion evaporation regime
复制标题
DOI：
10.1063/1.1598281
复制
发表时间：
2003-08
影响因子：
3.2
通讯作者：
I. Romero-Sanz;R. Bocanegra;J. F. D. L. Mora;M. Gamero-Castaño
中科院分区：
文献类型：
--
作者：
I. Romero-Sanz;R. Bocanegra;J. F. D. L. Mora;M. Gamero-Castaño
在室温下，通过飞行时间质谱法研究了真空中离子液体 1-乙基-3-甲基咪唑鎓四氟硼酸盐 (EMI+BF4−) 泰勒锥体发出的全喷雾。在大多数研究条件下，电流主要由离子组成，但包含一小部分纳米液滴，这些纳米液滴往往主导发射的质量流。例外的是，液滴喷射在接近泰勒锥稳定的最小流速时消失。目前在除液态金属以外的其他物质的泰勒锥中发现稳定的严格离子状态很大程度上要归功于早期对硫酸的观察，其中大多数但不是全部电流都是离子的。最引人注目的是，这种纯离子状态是在电导率 K 仅 1.3 S/m 时获得的，远小于硫酸的电导率，并且小于 K>2 S/m 的甲酰胺电解质仍然发出大量下降电流的电导率。离子发射主要包括二聚体 (EMI–BF4)EMI+，根据...
The full spray emitted by Taylor cones of the ionic liquid 1-ethyl-3-methyl imidazolium tetrafluoroborate (EMI+BF4−) held in a vacuum is investigated at room temperature by time of flight mass spectrometry. The current is composed mainly of ions under most conditions studied, but contains a small component of nanometer drops that tends to dominate the emitted mass flow. Exceptionally, drop ejection vanishes close to the smallest flow rate at which the Taylor cone is steady. The present discovery of a stable strictly ionic regime in Taylor cones of substances other than liquid metals owes much to earlier observations with sulfuric acid, where most but not all the current was ionic. Most striking is the fact that this purely ionic regime is obtained at an electrical conductivity K of only 1.3 S/m, much smaller than that of sulfuric acid, and smaller than that at which formamide electrolytes with K>2 S/m do still emit substantial drop currents. The ion emission includes primarily the dimer (EMI–BF4)EMI+, acc...