Analyzing the Physico-Chemical Parameters of Detergents and Detergent Mixtures

The most important physico-chemical characteristics describing detergent micelles are the CMC value and the aggregation number. These parameters depend critically on external conditions such as pH, ionic strength, buffer composition or temperature. However, the influence of these conditions on CMC or aggregation number is a priori not to predict, but the most important parameter. This holds especially for the aggregation number. Here, we present a simple, reliable and fast method for the analysis of detergent containing buffer systems. It enables the determination of CMC values and aggregation numbers of detergents as well as detergent mixtures in a 96well plate standard device relying on steady state fluorescence and fluorescence quenching. To prove the general applicability of our approach, we analyzed DDM as a prime example of a detergent and mixtures of DDM with six other detergents at different ratios to demonstrate the potential of our method.