氖氩混合气体辉光放电发射光谱法测定钢样中铝的分析特性(英文)

Analytical performance of glow discharge optical emission spectrometry with neon-argon mixed gases in determination of aluminum in steel samples

研究了在Ne-Ar混合气体辉光等离子体中铝的原子及离子发射光谱线,并与纯Ar和纯Ne辉光等离子体进行了比较。在不同的放电气体环境下,Al发射线的相对强度不同。在Ne为放电气体时,可以观察到由4f→3d跃迁而产生的AlⅡ358.71 nm和AlⅡ358.66 nm两条发射线,而这两条线在以Ar为放电气体时不会产生。这种现象的原因是由于4f激发态是由Al原子和Ne离子的共振电荷转移碰撞而选择性高几率的产生的。由于亚稳态的Ne与Ar原子的彭宁碰撞会产生大量的Ar离子,因此在Ne等离子体中加入少量的Ar气时,会增加等离子体中气体离子的数量和电子密度。这种在Ne-Ar混合气体中发生的变化导致Al光谱线的发射强度增强。在Al的原子线和离子线中,AlⅡ358.641可被用来作为痕量Al检测的分析线。因为该线在Ne-Ar混合气体等离子体中的强度高,背景低。

The emission characteristics of several atomic and ionic line of Al emitted from a Ne-Ar mixed gas glow discharge plasma were investigated. In comparison with pure Ar and pure Ne plasmas, the relative intensities of the Al emission lines are much different among these plasma gases. The Al Ⅱ lines which are identified to the 4f-3d transitions, such as Al Ⅱ 358.71 nm and Al Ⅱ 358.66 nm, give intense emission when Ne is employed as the plasma gas, whereas these Al Ⅱ lines cannot be emitted from the pure Ar plasma. The reason for this effect is that the 4f excited levels are highly and selectiveiy populated through resonance charge transfer collision between Al atom and Ne ion. The addition of small amounts of Ar to the Ne plasma increases the population of gas ions as well as the number density of electrons in the plasma because Ar ions are predominantly produced through Penning ionization collision between Ne metastable and Ar atom. This change occurring in the Ne-Ar mixed gas plasma results in enhancement in the emission intensities of Al lines. Among the atomic and ionic Al lines, the Al Ⅱ 358. 641 nm line can be employed as an analytical line for determination of trace-level Al, since the intensity is large and the background equivalent concentration is small in the Ne-Ar plasma.