Kinetic analysis of additively overlapping reactions. Part 1. Description of an optimization method and its use for the separation of peaks

The determination of kinetic parameters for additively overlapping TG steps is possible only by fitting model equations (e.g., phase-boundary reactions) to the non-standardized weight step by means of non-linear optimization. A general condition of this procedure is the reproducibility of a conversion curve from a partial interval. Calculations carried out with theoretical and with erroneous values have shown that it is highly dependent upon the dispersion of the measured values and upon the position and length of the interval. In general, it is to be considered that the maximum must be involved in the evaluation. An increase in dispersion of the data can be compensated for by the evaluation of an enlarged partial interval.The findings obtained have been applied to the evaluation of additively overlapping reactions by the use of the procedure described. A general condition of a successful separation of the peaks is the existence of an overlapping-free interval including the maximum for only one of the overlapping partial reaction steps.     

Application of the generalized standard addition method to correction for the effects of peak overlap and intermetallic compound formation in potentiometric stripping analysis

Applications of the generalized standard addition method in potentiometric stripping analysis are presented. Accurate quantitative results can be obtained, even when the analytical signals are strongly affected by peak overlaps or by the formation of intermetallic compounds. The possibilities and limitations of the approach are discussed. An optimized experimental procedure for correction of the copper-zinc intermetallic interference is introduced.