A Ratiometric Fluorescent Assay for Fluazinam Based on FRET Between CdTe Quantum Dots and Porphyrin

Abstract

A fluorescent detection system for fluazinam was reported using fluorescence resonance energy transfer (FRET) method based on CdTe quantum dots (CdTe QDs) and 5, 10, 15, 20-tetrakis(4-methacryloyloxy) phenyl porphyrin (TMaPP). TMaPP and water-soluble CdTe QDs were synthesized successfully and characterized using FT-IR, 1H NMR, XPS and TEM, respectively. FRET mechanism between CdTe QDs and TMaPP was confirmed by detailed studies on their fluorescent spectra. After a co-culture of TMaPP and CdTe QDs, fluorescent intensity of CdTe QDs decreased significantly while that of TMaPP increased concomitantly due to altered FRET. Addition of fluazinam led to impaired energy transfer from CdTe QDs to TMaPP and therefore fluorescence recovery of CdTe QDs with fluorescence quenching of TMaPP. The correlation of fluazinam concentration with the fluorescence intensity ratio [Formula: see text] provided the basis for quantitative analysis, and a broad linear range varying from 0.01[Formula: see text][Formula: see text]M to 5[Formula: see text][Formula: see text]M with a low detection limit of 2.3[Formula: see text]nM was obtained. As-reported sensor system demonstrated excellent reproducibility, selectivity and sensitivity in real sample detection.