The electrochemical preparation of a novel composite glassy carbon/betaine/platinum (GC/BT/Pt) electrode with meso‐ nano Pt globules dispersed on the outer surface and betaine, as intermediate layer, electrodeposited on GC by Cyclic Voltammetry (CV) or Pulsed Potential (PP) techniques, is presented. Surface analysis by Scanning Electron Microscopy (SEM) and X‐ray Photoelectron Spectroscopy (XPS) confirms the strategic role of grafted betaine in modulating GC/BT‐ interaction sites and the range of potentials for adequate platinum CV electrodeposition. The GC/BT/Pt performance, concerning sensitivity, linearity, work potentials and repeatability tests with Flow Injection Analysis (FIA), was ascertained for the detection of vitamins B1 and B6.