Blue-light emitting aminated pectin for detecting Cu2+ ion

This research studied the chemo-sensing of low-cost aminated pectin (PE) obtained by a facile calcination under ammonia gas at temperature no higher than 175 °C without excessive use of alkaline, acid or solvents. The ammonia gas was found to replace the hydroxyl and methoxyl group, enhancing the crystallinity and solubility of the resultant pectin than those calcined in air or in 5% H 2 . Though the increase of light absorption could be attributed mainly to the dehydration during calcination which caused the formation of C C double bond or aromatic ring, the N incorporation could be important to the photoluminescence (PL) emission. The PL quenching of the blue fluorescent aminated pectin showed a good linearity with the concentration of Cu 2+ , Fe 3+ and the highest sensitivity toward Cu 2+ among the investigated metal ions. In order to further increase the PL quenching toward Cu 2+ and decrease the interference of Fe 3+ , a method involving H 2 O 2 and ultraviolet illumination was developed to catalyze the oxidation of fluorophores on the polymer. This work provides new horizon on the modification and application of pectin in chemosensing.