Vaporization process of SiO₂ particles for slurry injection in inductively coupled plasma atomic emission spectrometry

In this work, the vaporization process of SiO₂ particles in an ICP was theoretically and experimentally investigated. The emission intensity of Si I for the three different sizes of SiO₂ particles, 0.35, 1.4 and 2.5 μm, was measured as the observation height varied. Based on these experimental heights, the heat-transfer and mass-transfer models were applied in order to understand the vaporization process of SiO₂ particles in an ICP. When a heat-transfer-controlled model is considered for the process, the rate for a SiO₂ particle in the tested size became comparable to that obtained by experiment. SiO₂ particles in the range of 0.3-2.6 μm seemed to be vaporized by a heat-transfer-controlled mechanism, rather than by a Knudsen-effect-corrected heat-transfer-controlled or mass-transfer-controlled mechanism in an atmospheric pressure ICP.