Plasma Formed in Argon, Acid Nitric and Water Used in Industrial ICP Torches Plasma Formed in Argon, Acid Nitric and Water Used in Industrial ICP Torches (original) (raw)
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Plasma Formed in Argon, Acid Nitric and Water Used in Industrial ICP Torches
Plasma Science and Technology, 2012
Inductively coupled plasmas (ICPs) are used in spectrochemical analyses. The introduction of the sample by means of an aerosol are widely used. The introduction and the total evaporation of the aerosol is required in order to obtain a good repeatability and reproducibility of analyses. To check whether the vaporization of the aerosol droplets inside the plasma is completed, a solution could be used to compare the experimental results of the emission spectral lines with theoretical results. An accurate calculation code to obtain monatomic spectral lines intensities is therefore required, which is the purpose of the present paper. The mixtures of argon, water and nitric acid are widely used in spectrochemical analyses with ICPs. With these mixtures, we calculate the composition, thermodynamic functions and monatomic spectral lines intensities of the plasma at thermodynamic equilibrium and at atmospheric pressure. To obtain a self sufficient paper and also to allow other researchers to compare their results, all required data and a robust accurate algorithm, which is simple and easy to compute, are given.
Plasma Sources Science and Technology, 2011
The aim of the paper is to test the accuracy of classical spectroscopic methods in the visible domain dedicated to measurements of temperature and electron density in order to conclude about the validity of thermal disequilibrium. The influence of various factors is studied: accuracy of the intensity calibration, Abel inversion of the experimental spectra, excitation temperature deduced from the relative method, absolute excitation temperature, influence of the transition probability accuracy, influence of the Biberman factor value, electron temperature from the line-to-continuum intensity ratio, electron density deduced from Stark broadening, and electron density deduced from the continuum intensity. This spectroscopic investigation is carried out for argon plasma and argon copper plasma both produced by means of an ICP torch operating at atmospheric pressure. Results are given with uncertainties for each evaluated parameter. We show that, first, the electron temperature deduced from the line-to-continuum intensity ratio has to be considered with great care; second, for argon plasma no evidence of thermal disequilibrium can be discerned, whereas for argon copper plasma a small disequilibrium of 1.2 to 1.4 at most is experimentally observed.
Entrainment of ambient air into a spectrochemical inductively coupled argon plasma
Spectrochimica Acta Part B: Atomic Spectroscopy, 2003
A spectrochemical inductively coupled argon plasma (ICP) is normally operated in the open air. Therefore, it is suggested in the literature that entrainment of air molecules into such an ICP may cause loss of electrons, especially so at the plasma's edge. The present study discusses the significance of this effect. The density and temperature of electrons and nitrogen molecules around the edge of the plasma were measured by Thomson and rotational Raman scattering. A region where both electrons and nitrogen were present in detectable amounts (10 and 10 m , 19 24 y3 respectively) could not be observed. Above the torch inner wall the nitrogen concentration drops rapidly towards the plasma. Measurements suggest that the nitrogen concentration at 1 mm from the plasma is only a few percent, and in the active zones of the plasma (far) below 0.1%. This is not enough to affect the plasma significantly. Moreover, electron loss due to diffusion of nitrogen into the plasma is calculated to be much slower than the loss observed in earlier studies. Hence, air entrainment is unlikely to play a significant role in the ICP. A possible alternative is the formation and destruction of molecular rare gas ions. ᮊ
Spectrochimica Acta Part B: Atomic Spectroscopy, 1975
&&a&-Models of induction coupled plasma (ICP) discharges are developed for arrangements important in spectrochemical analysis. These models account for fhe spatial distribution of gas properties and major energy losses found in high temperature discharges. Realistic gas flows, and sample particle motion and decomposition are incorporated into the models. Computer simulations based on these models provide spatial temperature, gas velocity, sample concentration, and radiation distributions for a number of experimental ICP discharge configurations. The alteration of these distributions for various operskional parameters permits evaluation of some important factors in developing spectrochemical analysis with the ICP source. Recognized differences between theory and experiment are discussed.
The purpose of this article is to study experimentally and theoretically the spectral line ratios O 700.22 nm/N 746.87 nm with a sample gas mixture of N 2 and O 2 (notably for pure air) in an inductively coupled plasma (ICP) torch. We study theoretically the influence of the thermal disequilibrium on the composition and on the volumic enthalpy in a plasma produced in an ICP torch, and we show that the lower temperature in the plasma is set by the power supplied by the inductive coil. If the temperature (or heavy species temperature for plasma out of thermal equilibrium) is sufficiently low (<5000 K), we show that the thermal disequilibrium has no influence on intensity spectral line ratios (O 700.22 nm/N 746.87 nm). We compare these results with those obtained experimentally in the case of N 2 –O 2 mixtures, and we show that the determination of monatomic spectral line ratios (O 700.22 nm/N 746.87 nm) solely depends on the initial sample gas composition introduced in the ICP torch.
Applied Spectroscopy, 1987
An inductively coupled plasma spectrometer was modified for gaseous sample introduction. The system uses a gas proportioner utilizing rotameters to achieve sample gas concentrations and mixing with the sample argon gas. Modifications of instruments were performed to enhance stability and compatability of gaseous sample introduction. Instrument performance was characterized for optimization of spectral signals produced from plasma gases. Spectral analyses of gaseous samples including CF4, SF6, 02, N2, air, and mixtures of CF4-O~ and CF4-O2/Nz were performed. Identification of plasma gas and plasma-induced byproducts, both atomic and molecular, were determined.