Analysis of Biocidal Oligoguanidines and Oligobiguanides by High Performance Liquid Chromatogaphy and Mass Spectrometry

Oligoguanidines and oligobiguanides are in general use as antiseptics and disinfectants. They consist of complex mixtures of oligomers with different structures and varying chain length, so that a thorough chemical characterization of these products remains challenging. In the present work, high performance liquid chromatography was investigated as a tool for separation of oligoguanidines obtained from polymerization of guanidine and a diamine, as well as of oligobiguanides obtained from hexamethylenebiscyanoguanidine and hexamethylenediamine. Efficient separations could be achieved under reversed-phase conditions using gradient elution with water (acidified by 0.1% trifluoroacetic acid) and acetonitrile. Structure elucidation of separated peaks was done by mass spectrometric detection. This approach was not only suited for characterization of products obtained under different synthesis conditions, but could also be successfully applied to residue analysis in environmental water samples after extraction and preconcentration by solid-phase extraction. Preconcentration factors up to 10000 were possible by mixed-mode sorbents exhibiting both reversed-phase and ion-exchange properties. Keyword: Oligoguanidines; Oligobiguanides; Biocides; Liquid chromatography; Mass spectrometry