Optimizing analytical methods

Questions frequently arise, especially during the development phase of analytical methods, about how to optimize parameters, such as reaction time, concentration of reagents, etc. and how to optimize analysis procedure, e.g. extraction method, choice of reagent, etc. Questions constantly crop up, e.g. What effect do pH and EDTA level have on the extraction of a metal ion by means of a chelating agent - or What significance do pH and redox potential have in the desorption of heavy metals from sands  

Parametric tests (t-test, F-test) are not really adequate for answering the sort of question mentioned above, since they require a standard distribution of the population and can only compare 2 components with each other at any one time. A better solution is offered above all by variance analyses or factorial experiment planning and evaluation. 

Alternatively one can fall back on methods used in operations research, such as the simple or revised Simplex method, the Uniplex method, etc. A more detailed description with practical examples and suggestions for 

---

AUC Optimal Analytic Method for Each Database and Outcome... 

A typical example of single-stage derivatization of amino acids is based on their reaction with methyl or phenyl isothiocyanates with the formation of 3-methyl (phenyl) thiohydantoins. The optimal analytical method for the analysis of semivolatile organic compounds of this class is RP HPLC, but derivatives of the simplest amino acids can be objects of GC analysis as well (Fig. 3). 

The key difference between the complex 170 and the more simple 171 is the choice of values for experimental parameters. Cost and instrumental complexity of these analog instruments were increased by providing variable pulse amplitude, and even more so by variable pulse width. Because the pulse width is the parameter which establishes the experimental time scale, it typically must be varied in any mechanistic study, and it is highly advantageous to have a selection of pulse widths available when optimizing analytical methods. Thus in instrument design there is a clear tradeoff between power of the technique and cost of its implementation. 

Kurtz SM, Muratoglu OK, Buchanan F, Currier B, Gsell R, Shen FW, et al. Interlaboratory studies to determine optimal analytical methods for measuring the oxidation index of UHMWPE. Biomaterials 200T,22(21) 2875-81. 

---