Highly selective fluorescent sensor based on electrosynthesized oligo(1-pyreneboronic acid) enables ultra-trace analysis of Cu2+ in environment and agro-product samples

A dissolvable conjugated polymer oligo(1-pyreneboronic acid) (OPYBA) as the fluorescent sensor was facilely electrosynthesized for highly selective analysis of Cu2+ at ultra-trace levels in real samples. OPYBA was obtained by potentiostatical electropolymerization of corresponding monomer at 1.0 V vs. Ag/AgCl in acetonitrile containing tetrabutylammonium tetrafluoroborate and dedoped with dilute HCl. The tetrahydrofuran-solvable OPYBA showed good fluorescent properties and could specifically recognize Cu2+, and then it was employed for the quantification of Cu2+ in linear ranges of 25 pM–88.2 μM and 188 μM–750 μM with a low detection limit of 23 pM. As the fluorescent sensor, OPYBA displayed a high sensitivity and selectivity for Cu2+ over other substances existing in environment and agro-products such as metal ions, anions, organic acids, amino acids, and carbohydrates. Also, it was used to detect Cu2+ in tap water, lake water, white rice, Chinese cabbage, and cropland soil samples with satisfactory results, revealing that OPYBA could be as a practical sensing platform for ultra-trace analysis of Cu2+ in environment and agro-product samples.