Calculation of kinetic parameters from chamber tests using nonlinear regression

Different functions of exponential type, which are relevant for the mathematical modeling of test chamber kinetics are examined. The degrees of freedom, the time range and the noise level are systematically varied. The possibilities and limitations for the recovery of kinetic parameters are tested with nonlinear regression analysis by the use of experimental and synthetic data sets. An equation is presented, which allows superimposing the generated data with accurate noise characteristics. As equation are tested with parameter uncertainties being obtained from the inverted covariance matrix are found to be unreasonably large for a limited number of data pairs and it is shown that error estimation using the confidence region at the 68.3% level gives more reliable results. It is demonstrated how the analysis of simulated data can yield valuable information about the conditions being necessary to obtain reliable results from test chamber experiments.