A nebulizer design for inductively coupled plasma spectrometry

用于电感耦合等离子体光谱测定的雾化器设计

• 批准号: 530363-2018
• 负责人: Ashgriz, Nasser
• 金额: $ 1.98万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=644207
• 关键词: nebulizer; design; inductively; coupled; plasma

Inductively coupled plasma optical emission spectroscopy (ICP-OES) and mass spectrometry (ICP-MS) can be considered as the most important tools in inorganic analytical chemistry. In these system, a liquid sample is atomized into small droplets and introduced into a plasma. For a proper operation, the droplet sizes should be small, preferably less than 5 microns. Most commercially available systems use pneumatic nebulizers, which generate a broad range of droplet size distributions, mainly in the range of 1-100 microns. Therefore, a spray chambers is added downstream of the nebulizer to remove large droplets. This, however, results that only a small fraction (less than 5%) of the nebulized sample actually contributes to the measured signal. For very small sample sizes, micro-nebulizers are used, which have very small size orifices to generate small droplets for small sample uptakes. However, these systems are prone to blockage and clogging, in particular for high viscosity solutions and solutions containing total dissolved solid, making them basically impractical. ****Despite a significant amount of research and the high number of publications devoted to liquid sample introduction, this problem still persists to be what limits the efficiency of atomic spectrometry.**We are proposing a novel method for the nebulization of liquid samples, which we believe would significantly improve the efficiency of ICP systems. The proposed method is based on using an ultrasound nebulizer in combination with a controlled gas mixing system to limit the droplet collision and coalescence. Ultrasound nebulizers can be designed to generate very small droplets (~ 5micorns). However, the droplet sizes at certain frequencies also depends on the liquid properties. One objective of the present research is to determine this dependency for a wide range of practical fluid properties, and determine the ultrasound frequency and amplitude needed to keep the droplet sizes small for a relatively higher viscosities (up to 100 cP). Another objective of the present research is to develop a mixing chamber to rapidly disperse the high density aerosol that is generated by the ultrasound nebulizer in order to prevent secondary collision and coalescence, which may result in an increase in droplet sizes. ****

电感耦合等离子体发射光谱（ICP-OES）和质谱（ICP-MS）可以被认为是无机分析化学中最重要的工具。在这些系统中，液体样品被雾化成小液滴并引入等离子体中。为了正确操作，液滴尺寸应该很小，最好小于 5 微米。 大多数商用系统都使用气动雾化器，它产生各种液滴尺寸分布，主要在 1-100 微米范围内。因此，在雾化器下游增加雾化室以去除大液滴。然而，这导致只有一小部分（小于 5%）雾化样品实际上对测量信号有贡献。 对于非常小的样品量，使用微雾化器，其具有非常小的孔口，可以产生小液滴以吸收少量样品。然而，这些系统容易堵塞和堵塞，特别是对于高粘度溶液和含有总溶解固体的溶液，使得它们基本上不切实际。 ****尽管针对液体样品引入进行了大量的研究和大量出版物，但这个问题仍然存在，这限制了原子光谱测定的效率。**我们提出了一种用于液体样品雾化的新方法，我们相信这将显着提高 ICP 系统的效率。 所提出的方法基于使用超声雾化器与受控气体混合系统相结合来限制液滴碰撞和聚结。超声波雾化器可设计为产生非常小的液滴（~ 5 微米）。然而，某些频率下的液滴尺寸也取决于液体特性。本研究的一个目标是确定各种实际流体特性的这种依赖性，并确定在相对较高的粘度（高达 100 cP）下保持较小液滴尺寸所需的超声波频率和振幅。 本研究的另一个目标是开发一种混合室，以快速分散超声雾化器产生的高密度气溶胶，以防止二次碰撞和聚结，这可能导致液滴尺寸增加。 ****