I am looking for an applikation for measurement of LAS by HPLC - Do you have experience with such an analyse - I will be happy to hear about it.

LAS is best analyzed using a C-18 column, water-ACN eluent containing at least 10mM electrolyte. As you are probably aware this is actually a mixture of 30-50 related compounds so you shouldn't be expecting to see a single peak or even to see all peaks resolved. Generally, components elute in groups (e.g. all LAS components with a C10 hydrophobe, then all LAS components with a with C12 hydrophobe, etc., with partial resolution of the different branch structures containing the same carbon number). Detection can be either via UV or conductivity (in the latter case a suppressible electrolyte such as ammonium borate-boric acid should be used). Joachim Weiss' book: Ion Chromatography (second edition) has more details.