Transforming glucose into fluorescent graphene quantum dots via microwave radiation for sensitive detection of Al3+ ions based on aggregation-induced enhanced emission

Abstract

This paper initially describes a nanosensor for fluorescence detection of Al³⁺ ions by using graphene quantum dots (GQDs) that are synthesized via microwave-assisted single-step ring-closure condensation of glucose molecules. The one-pot synthesis strategy based on the microwave radiation could be finished in several minutes and no post-modification of the GQDs was required. In particular, the GQD nanoprobes showed a sensitive and specific fluorescence enhancement response to Al³⁺. The involved mechanism might be the Al³⁺-mediated aggregation of the GQDs leading to aggregation-induced enhanced emission (AIEE). Under optimal conditions, this new fluorescent nanosensor was able to quantitatively detect Al³⁺ in a linear concentration range of 0.4–500 μM. The limit of detection was estimated to be ∼59.8 nM according to the 3σ rule, which made it be among the most sensitive systems currently available for sensing the target ion. Moreover, satisfactory recovery results (ranging from 96.8 to 109.7%) of analyzing a set of real water examples additionally validated its accuracy for practical applications. Considering its simplicity, high sensitivity and specificity, low cost, and good reliability, the developed fluorescent nanosensing system for Al³⁺ holds great promise for broad uses in water safety, environmental monitoring, and waste management.