Evaluation of the amount of elements released from an ICP into the atmosphere and zero emission in ICP-MS

电感耦合等离子体质谱仪的元素发射为了采集通过质谱仪管道的元素，制作了一套带滤膜的采样系统。过滤器被放置在市售的用于减压过滤的支架中。金属管的一端(直径2毫米)被带到过滤器附近，另一端插入到管道的中心。在血浆中加入10μg Yb/ml的溶液时，将通过导管的部分分析物收集在过滤器上30min。收集的样品颗粒通过超声波解吸成5毫升的0.1M硝酸。虽然样品溶液中的分析物是用石墨炉原子吸收法测定的，但没有观察到峰，因此无法定量测定从电感耦合等离子体质谱发射的分析物的量。这可能是由于使用了内径较小的管道所致。为了定量测定电感耦合等离子体发射到环境中的元素的量，有必要改进采样系统。针对低压氦-电感耦合等离子体质谱难以连续将水溶液引入低压电感耦合等离子体质谱中的问题，本实验室研制了超声雾化器。产生的样品气雾剂被雾化气体输送到去溶装置。样品导入系统和等离子体之间的聚四氟乙烯-毛细管界面使雾化器能够在常压条件下运行并稳定地引入样品溶液。用朗缪尔探头进行血浆诊断。用低压氦-电感耦合等离子体测得的电子温度优于用氩-电感耦合等离子体测得的电子温度。这些结果表明，电子与高能电子的碰撞增强了被分析物在低压氦-电感耦合等离子体中的电离。结果表明，低压氦-电感耦合等离子体是实现电感耦合等离子体质谱零排放的一种很有前途的离子源。

The emission of elements from ICP mass spectrometer In order to collect the elements passing through the duct of a mass spectrometer, a sampling system with a membrane filter was made. The filter was set in a commercial available holder used for decompression filtration. One end of a metallic pipe (2 mm i.d.) was brought near to the filter and the other end was inserted into the center of the duct. While a solution of 10 μg Yb/ml was introduced into plasma, a part of analyte passing through the duct was colleted on the filter for a period of 30 min. The sample particles collected on the filter was desorbed into 5 ml of 0.1 M HNO_3 by irradiating ultrasonic wave. Although the analyte in the sample solution was determined by GF-AAS, no peak was observed, and consequently, the amount of analyte emitted from ICP-MS could not be measured quantitatively. This is probably due to the use of the pipe with small inner diameter. It is necessary to quantitatively determine the amount of elements emitted from ICP into the environment by improving the sampling system.Low-pressure helium-ICP-MS Since it was difficult to continuously introduce aqueous solutions into low-pressure helium-ICP, a ultrasonic nebulizer was constructed in our laboratory. The generated sample aerosol was transported to a desolvation unit by the nebulizer gas. A PTFE-capillary interface between the sample introduction system and plasma enabled the operation of the nebulizer under atmospheric pressure conditions and the stable introduction of sample solutions. The plasma diagnosis with a Langmuir probe was made. The electron temperature measured for low-pressure helium-ICP was superior to that for argon-ICP. These results suggest that the ionization of analytes in the low-pressure helium-ICP was enhanced by electron impact with high-energy electrons. It was found that low-pressure helium-ICP is a promising ion source for zero emission in ICP-MS.