Axial signal profiles of analyte molecular, atomic, and Ionic species contain Information essential for mechanistic studies of analyte transformation. Such profiles are easier to deal with theoretically than radial profiles because the central channel is much less heterogeneous than any other part in the plasma. The large regions often Investigated in spatially resolved measurements render the conventional local thermal equilibrium-based models Inappropriate for mechanism elucidation. A more general dynamic model is established, where equilibria and steady states are considered as special cases. Kinetics of rate-determining reactions such as dissociation, atomization, ionization, and recombination are considered. For mathematical simplification, we Imagine that the vapor plume results from a single aerosol particle, and the kinetic processes taking place are then closely followed. In our case, diffusion is approximated as volume expansion under constant pressure. The resultant analyte distribution observed should then be a good approximation to the real one, assuming an Inductively coupled plasma with reproducible experimental conditions and a uniform solution droplet size distribution. By comparison of the simulated height profiles using different rate constants with experimental height profiles, analyte transformation can be more precisely described. On the other hand, measurements of experimental height profiles and evaluation of statistic moments should allow estimation of reaction rate constants.