Capillary isotachophoresis of piperidinoethylethers of the alkoxyphenylcarbamic acids

Abstract

Conditions for the separation and determination of N-[2-(alkoxyphenylcarbamoyloxy)-ethyl]-piperidinium chlorides ( analogues of heptacaine) by the capillary isotachophoresis have been studied. For the successful separation of lower alkoxy derivatives the acetate buffer solution, pHL = 4.75, was found to be a suitable leading electrolyte (K+ as the leading ion) and β-alanine a suitable terminator. The separation can be achieved even in the acid medium with H+ as the leading ion and with a voluminous terminating cation. For instance, pseudoaconitine or N-[2-(2-heptyloxyphenylcarbamoyloxy)-ethyl]-benzylpiperidinium chloride were found to be acceptable. The steric hindrance of the solvation, characteristic for 2-alkoxy isomers, makes their separation from 3- or 4-alkoxy isomers possible, with the exception of methoxy derivatives.