Optimization studies of some analytical chemical methods

The following analytical chemical problems have been studied: the extraction of iron (II) from water to cyclohexane using hexafluoroacetylacetone and tri-n-butyl phosphate; the separation of the isomers of benzenedicarboxylic (phthalic) acid using reverse-phase high performance liquid chromatography (RPHPLC); and the separation of benzoic acid, 2-aminobenzoic acid, 4-aminobenzoic acid, 4-hydroxybenzoic acid, and 1,4-benzenedicarboxylic acid using RPHPLC. Selected parameters in each study were varied using optimization strategies to examine the effects of the parameters upon the chosen analytical methods and problems. A brief explanation of each optimization strategy is presented. A discussion of the utility of the strategy in each particular case is also presented. Models are utilized to examine the behavior of the analytical chemical methods and the chemical systems being investigated: to more fully understand the performance characteristics of the methods; to aid in the prediction or verification of "true" optimum parameter conditions; and to specify factor tolerances for a method. Where specific optimum conditions for a method are predicted, these optimum parameter levels are examined by the performance of additional experiments to evaluate the analytical performance of the method at the specified conditions.