In the state of the art I had come across that scientist have treated commercial styrene-divinyl benzene (non-polar, non funtionalized) polymeric beads with 25% glutaraladehyde (GA) solution for few mins to h. Followed by buffer wash to remove the unreacted GA, and the GA treated beads were use for covalent immobilization of enzymes. I want to understand the chemistry how does and were this GA forms bonds over polymeric beads??