Analytical & Testing Center, Sichuan University, Chengdu, Sichuan 610064, China.
Key Lab of Green Chemistry & Technology of MOE, and College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China.
Anal Chem. 2022 May 31;94(21):7683-7691. doi: 10.1021/acs.analchem.2c01105. Epub 2022 May 12.
A compact tandem excitation source-in-source was designed by arranging a point discharge (PD) ignited in argon/hydrogen (Ar/H) flame and utilized for boosted excitation for the optical emission of chromium. Through a tungsten coil (W-coil) electrothermal vaporizer (ETV) located right under the tandem source without any interface for sample introduction, a miniaturized optical emission spectrometer was realized. Because the discharge gaseous atmosphere of PD was activated in the flame, the energy consumption of PD for breaking down discharge gas and maintenance of plasma was greatly saved. In addition, the flame could partially atomize or keep the atomized state of analyte atoms through its reducing environment. Therefore, the excitation capability of the tandem source was greatly improved, owing to the synergistic effect of PD microplasma and Ar/H flame. In addition, part of the analyte was atomized/excited on the W-coil, and thereby, dry, pure, and activated analyte species were released from the W-coil and swept into the tandem source for atomization/excitation. Through the collective effect of W-coil ETV, Ar/H flame, and PD microplasma, analytical sensitivity for Cr was greatly enhanced. Under the optimized conditions, with 10 μL sample solution, a limit of detection of 1.5 μg L and a relative standard deviation of 3.6% (20 μg L, = 5) were achieved. Its accuracy was demonstrated by successful analysis of several certified reference materials. Owing to the advantages including high sensitivity, compactness, and cost effectiveness, it is promising to facilitate the miniaturized spectrometer for more elements and potential field analytical chemistry.
设计了紧凑的串联激励源，由在氩/氢 (Ar/H) 火焰中点燃的点放电 (PD) 和利用其增强铬的光发射的增强激励组成。通过位于串联源正下方的钨丝线圈 (W-coil) 电热蒸发器 (ETV) ，无需任何接口进行样品引入，实现了小型化的发射光谱仪。由于 PD 的放电气体气氛在火焰中被激活，因此大大节省了 PD 用于分解放电气体和维持等离子体的能量消耗。此外，火焰可以通过其还原环境部分原子化或保持分析物原子的原子化状态。因此，由于 PD 微等离子体和 Ar/H 火焰的协同效应，串联源的激励能力大大提高。此外，部分分析物在 W-coil 上被原子化/激发，因此，干燥、纯净且激活的分析物从 W-coil 中释放出来并被扫入串联源进行原子化/激发。通过 W-coil ETV、Ar/H 火焰和 PD 微等离子体的集体作用，Cr 的分析灵敏度大大提高。在优化条件下，对于 10 μL 样品溶液，检测限为 1.5 μg L，相对标准偏差为 3.6%（20 μg L，n=5）。通过成功分析几个认证参考物质证明了其准确性。由于具有高灵敏度、紧凑性和成本效益等优点，有望促进更元素和潜在现场分析化学的小型化光谱仪的发展。
