Sensitive detection of quorum signaling molecules (N-acyl homoserine lactones) in activated sludge based on surface molecularly imprinted polymers on CQDs@MIL-101†
N-Acyl homoserine lactones (AHLs), as typical signaling molecules in quorum sensing systems, play a key role in identifying the performance of activated sludge and microbial activities. Herein, a molecularly imprinted polymer composite material (CQDs@MIL-101@MIPs) was prepared under controlled conditions using a metal–organic framework (MIL-101) as the carrier material, carbon quantum dots (CQDs) as the fluorescent probe, and 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) as the template molecule by a surface imprinting technique, which was utilized for the rapid and sensitive detection of activated sludge quorum-sensing signaling molecules. After the elution of the template molecules, blotted cavities capable of selectively recognizing AHLs were formed on the surface of CQDs@MIL-101@MIPs. This composite material showed a linear fluorescence intensity with different target concentrations; the linear detection range was 0.2–2.0 μM, and the limit of detection (LOD) was 0.21 μM. The fluorescence method based on CQDs@MIL-101@MIPs was utilized to detect and analyse activated sludge samples with recoveries of 95.2–117.9%. As a stable and straightforward detection method, the CQDs@MIL-101@MIPs based fluorescent sensor has the potential to be utilized for the rapid and sensitive detection of AHLs in real samples.