Five different glass sheathing devices were used to introduce 20 mL min⁻¹ N₂ sheathing gas around the effluent from the spray chamber to see the effect of their dimensions on plasma robustness as measured using the Mg II 280.270 nm/Mg I 285.213 nm emission signal ratio in inductively coupled plasma (ICP) optical emission spectrometry (OES). A clear relationship between device dimensions and the plasma robustness profile along the ICP central channel was observed. With an aerosol inlet having an inner diameter of 1.0 cm in the sheathing device, mixing of N₂ with the aerosol was minimised and the resulting sheath increased robustness, the higher thermal conductivity of N₂versus Ar likely improving energy transfer between the bulk plasma and the central channel. The configuration of the outlet is also important, as any bottleneck favours mixing of N₂ with the aerosol, which in turn cools the plasma, thereby shifting the region of maximum robustness to higher above the load coil. Regardless of device dimensions, plasma robustness was always better with N₂ sheathing gas. An increased ion-to-atom emission signal ratio also resulted for other elements than Mg. The presence of N₂ also seems to affect excitation mechanisms, such as charge transfer between NO⁺ and Cd or Ni, which appears to take place at higher observation height, after N₂ has had enough time to diffuse into the central channel.

中文翻译：

---

护套设备通过氮气流提高电感耦合等离子体发射光谱仪的耐用性的比较研究†

使用五种不同的玻璃护套设备在喷雾室流出物周围引入20 mL min ^-1 N ₂护套气体，以观察其尺寸对使用Mg II 280.270 nm / Mg I 285.213 nm发射信号测得的等离子体强度的影响电感耦合等离子体（ICP）光学发射光谱（OES）中的比率。观察到器件尺寸与沿ICP中心通道的等离子体坚固性轮廓之间存在清晰的关系。与气溶胶入口具有1.0厘米的护套装置的内径中，N混合₂与被最小化气雾剂，将所得鞘增加的鲁棒性，N的高的热传导率₂与Ar可能会改善体等离子体与中央通道之间的能量转移。出口的配置也很重要，因为任何瓶颈都倾向于将N ₂与气雾剂混合，从而冷却等离子体，从而将最大耐用性区域移至负载线圈上方的较高区域。无论设备尺寸大小如何，使用N ₂护套气时的等离子体坚固性始终更好。除镁以外的其他元素也导致离子与原子发射信号比增加。N ₂的存在似乎也会影响激发机理，例如，在N ₂之后，NO ⁺与Cd或Ni之间的电荷转移似乎发生在更高的观察高度上。 已经有足够的时间扩散到中央渠道。