Effect of pasting liquids on the extraction of vitamin K1

Abstract

Atactic polypropylene, petroleum jelly, paraffin oil, paraffin wax, and several types of silicone oils were used for preparation of the respective glassy carbon paste electrodes (GCPEs) selected thanks to their stability in an aqueous-acetonitrile mixture. Each GCPE contained always 20% (w/w) of the pasting liquid chosen. In order to select the most suitable one, electroanalytical performance of the individual pasting liquids for extracting 100 µmol L-1 phylloquinone (vitamin K1) as a model compound was studied with the aid of the sequent square wave voltammetry and when using a speed of stirring 400 min-1 for 5 min (i.e. open circuit conditions). From experimental data obtained in these tests, it has been concluded that a viscous silicone oil of the MW 8000 type can be selected as the most suitable component.