Silica-based mesoporous ion-imprinted fluorescent sensors for the detection of Pb²⁺ in aqueous environments

Abstract

In this work, an environment-friendly core-shell material based on CDs@SiO2 as the core and mesoporous ion-imprinted layer as the shell was reported. As a highly sensitive and accurate fluorescent sensor for the detection of Pb2+ in environmental water, the composition combined ion imprinting technology with quantum dots to selectively quench the fluorescence of CDs by metal coordination in the presence of Pb2+, and the visual change of gradually weakening blue color could be observed by the naked eye for visual detection. The mesoporous structure significantly improved the detection recognition rate of CDs@SiO2@MIIPs.The molecularly imprinted sensor presented a favorable linear relationship over a Pb2+ concentration range from 10 nmol/L to 100 nmol/L and a detection limit of 2.16 nmol/L for Pb2+. The imprinting factor of the CDs@SiO2@MIIPs was 5.13. The sensor has a fast detection rate, is highly selective in the identification of Pb2+, and can be reused up to 10 times. The applicability of the method was evaluated by the determination of Pb2+ in spiked environmental water samples with satisfactory results.