Quantitative detection of double bonds in hyaluronic acid derivative via permanganate ion reduction

The detection of double bonds in polymers exploited as scaffold materials, e.g. hyaluronic acid (HA) derivatives, is crucial for their further applications. The quantity variations of unsaturated units significantly affect the photoinduced crosslinking degree responsible for the mechanical properties of scaffolds. We demonstrate a simple, selective and rapid quantitative method that enables the detection of double bond moieties in polymers. The approach is based on a reaction with potassium permanganate which is spectrophotometrically confirmed. The effect of glycidyl methacrylate concentration and various reaction catalysts introduced at the stage of HA modification, as well as the change of double bond concentration over time, has been investigated using the proposed method. In addition, the developed quantitative method can be utilized for rapid and efficient detection of unreacted double bonds after photopolymerization as a tool for monitoring conversion over time.