Data-pair method

Fig. 61 Application scheme according to the data pair method — Vj to V3 = standard solutions, U] to U3 = sample solutions...

In quantitative TLC, a corresponding number of standards are applied along with the samples and are also determined. The positioning of the samples and standards on the plate is of great importance for the analytical result. Our experience, gained during a course on quantitative TLC with Prof. Jork in Saarbriicken, confirms the superiority of the Data Pair Method, and this is therefore the only sample application scheme described in this book. In the data pair method, published by Bethke, Santi and Frei [40], all the solutions are applied twice, but not next to each other, and are separated by half the width of the plate. Figure 37 shows an application scheme of this type. 

For quantitative analysis, a special positioning scheme for manual or automatic application called the data pair method has often been recommended for reducing systematic errors owing to chromatographic parameters and obtaining the best densitometric results. In this method, all solutions are applied twice, with... 

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