Removal of metal ions using metal-flavonoid-DNA adduct protocol

An attempt has been made to incorporate intercalation power of metal-flavonoids (metal-Fls) into ds.DNA for selective accumulation of heavy metal ions on DNA trapping water insoluble (3-aminopropyl)triethoxysilane (APTES) films. Three flavonoids (Fls) namely primuletin (prim), morin (mor) and quercetin (quer) were used to chelate heavy metal ions alone and through calf thymus DNA intercalation. Metal ion (M?=?Cu²⁺, Fe³⁺, Cr³⁺, As²⁺, Hg²⁺, Pb²⁺, Cd²⁺, Sb⁵⁺) captured from 10?µM solution of its salt over Fl-DNA-APTES film was found to be more efficient towards metal ion removal (99% removal) than M-Fl interaction into DNA-APTES (80% removal) which in turn was better than M-Fl-DNA trapping into APTES (60% removal). M-Fl chelation was 1:1 for all the complexes and binding strength (K_b in M^?1) was of the order of 10³–10⁵ for different flavonoids (Fls) and the flavonoid-chelated metals (M-Fls). From the results, it was inferred that the nature of interaction between different constituents and metal chelation with the flavonoid are the key factors that affect the ion removal efficiency. It was also anticipated that any flavonoid can be used for ion removal process subject to its affinity strength towards the ion of interest. The work successfully demonstrated the usefulness of the method for ion removal in chemical, biological and environmental systems.