Autofluorescent Hyperbranched Poly(amide amine) as Effective Fluorescent Probe for Label-free Detection of Copper(II)...

A label-free fluorescent probe based on autofluorescent hyperbranched poly(amide amine) (HPAMAM) for copper ions was designed. HPAMAM is a cationic polymer containing many amino groups, which could bind Cu²⁺ ions to form cupric amine complexes, leading to a selective quenching of the fluorescence intensity of HPAMAM via inner filter effect. The fluorescence intensity of HPAMAM decreased with increasing concentration of Cu²⁺ ions and the linear response ranged from 0.05 to 25 μM (R² = 0.995), with the corresponding detection limit (3σ/k) of 17.15 nM. The HPAMAM fluorescent probe provided a simple, rapid, selective and sensitive fluorometric method for detecting Cu²⁺ ions, which could be also applied for detection of Cu²⁺ ions in real water samples.