ABSTRACT
A new inductively coupled plasma (ICP) torch with an air-cooling system has been designed and developed for both argon and helium plasma. The same torch and impedance-matching network could be used to generate stable Ar- and He-ICP. The torch consists of three concentric quartz tubes. The carrier gas, plasma gas, and cooling gas flow through the intervals between each tube. In an experiment, it was found that Ar-ICP could form a stable plasma under the following conditions: RF power of 1 kW, plasma gas flow rate of 11 L min(-1), and cooling gas flow rate of 20 L min(-1). For He-ICP, an input RF power of 2 kW, which is two-times higher than that of a conventional He-ICP, could be constantly applied to the plasma with plasma gas and cooling gas flow rates of 15 and 20 L min(-1), respectively. Using this torch, it is possible to realize lower plasma gas consumption for Ar- and He-ICP and a high-power drive for He-ICP. It has been found that the air-cooling gas stabilizes the shape of the plasma due to the pressure difference between the cooling gas and the plasma gas.
ABSTRACT
We developed an injection gas heating system for introducing large droplets, because we want to effectively to measure elements in a single cell. This system was applied to ICP-atomic emission spectrometry (ICP-AES), to evaluate it performance. To evaluate the effect of the emission intensity, the emission intensity of Ca(II) increased to a maximum of tenfold at 147°C and the peak was shifted upstream of the plasma. To investigate in detail the effect of an injection gas heating system, we studied different conditions of the injection gas temperature and droplet volume. When the injection gas temperature was 89°C, smaller droplets were easily ionized. At 147°C, the emission intensity ratio and the absolute amount of the sample including the droplet exhibited close agreement. These results show the advantages of the injection gas heating system for large droplet introduction, and the sufficient reduction in the solvent load. The solvent load could be reduced by heating to 147°C using the system.
