新型蒸发进样-微等离子体小型化原子发射光谱仪的研制

Miniaturization is one of the developing trends for current analytical instruments today, which is especially urgent for atomic spectrometry (AS). However, the complicated instrumental structures, high power consumption of traditional AS instruments remain an impediment for their miniaturization. Microplasma such as dielectric barrier discharge (DBD) and point discharge (PD) with advantages of small size, low power consumption and simple operation, has been increasingly used as the atomizer/excitation source in emission spectrometry. However, low power of microplasma results in limited excitation capacity, low sensitivity, and limited elemental scope; furthermore, the stability of microplasma is significantly affected by the solvent and matrix from sample. Therefore, we here proposed a hyphenation of the tungsten coil electrothermal atomization/vaporization (W-coil ETA/V) and the microplasma (dielectric barrier discharge or point discharge), establishing a miniaturized tungsten coil - microplasma atomic emission spectrometer. The heating program of electrothermal atomization/vaporization could easily remove the solvent and matrix of samples, and excitation capacity of microplasma as well as the sensitivity will be improved through the tandem atomizer/excitation source. The combination with chemical vapor generation for pre-separation and pre-concentration will further improve sensitivity and minimize matrix interference. The study of mechanism of atomization/excitation and the characteristics of microplasma will be helpful for improvement of the analytical performance of microplasma and extension of applications of microplasma in analytical atomic spectrometry.

小型化是当今分析仪器发展的新潮流之一，原子光谱分析法作为元素分析的重要手段，其仪器小型化更是迫在眉睫。但传统的原子发射光谱仪的核心部件原子化器/激发源结构复杂、能耗高，不易小型化。介质阻挡放电与尖端放电微等离子体具有体积小、功耗低等优点，已越来越多地被用作发射光谱分析的激发源。然而微等离子体功率低使其激发能力有限，进而导致分析灵敏度较低、可分析元素有限，且易受样品水分和基体的干扰。本项目拟将钨丝电热原子化/蒸发与介质阻挡放电和尖端放电联用，构建小型化钨丝-微等离子体原子发射光谱仪。通过电热蒸发消除样品水分及基体对微等离子体的影响，同时串/级联原子化器/激发源可增强微等离子体的原子化/激发能力进而提高分析灵敏度；结合化学蒸气发生与钨丝热捕集可进一步提高灵敏度与减小干扰。另外通过对原子化/激发机理及微等离子体性质的研究可进一步改善微等离子体分析性能，以及扩展微等离子体在原子光谱分析中的应用。

小型化是当今分析仪器发展的新潮流之一，原子光谱分析法作为元素分析的重要手段，其仪器小型化更是迫在眉睫。但传统的原子发射光谱仪的核心部件原子化器/激发源结构复杂、能耗高，不易小型化。微等离子体具有体积小、功耗低等优点，已越来越多地被用作原子发射光谱分析的激发源。然而微等离子体的低功率使其激发能力有限，进而导致分析灵敏度较低、可分析元素有限，且易受样品中水分与基体的影响。本项目将化学蒸气发生、电热原子化/蒸发与介质阻挡放电、尖端放电微等离子体联用，构建小型化微等离子体原子发射光谱仪。通过蒸气进样减少或消除样品水分与基体对微等离子体的影响，同时串/级联原子化器/激发源可增强微等离子体的原子化/激发能力进而提高分析灵敏度。项目主要完成了：（1）氢化物发生-尖端放电微等离子体原子发射光谱分析，（2）光化学蒸气发生-尖端放电微等离子体原子发射光谱分析，（3）钨丝电热蒸发-介质阻挡放电微等离子体原子发射光谱分析，（4）钨丝电热蒸发-尖端放电微等离子体原子发射光谱分析。结合化学蒸气发生与钨丝捕集可进一步提高灵敏度与减小干扰。另外通过对原子化/激发机理及微等离子体性质的研究可进一步改善微等离子体的分析性能，以及扩展微等离子体在原子光谱分析中的应用。研究成果方面，发表论文3篇（2篇Analytical Chemistry，1篇Journal of Analytical Atomic Spectrometry），获得授权专利1项。