Determination of norfloxacin or ciprofloxacin by carbon dots fluorescence enhancement using magnetic nanoparticles as adsorbent

A multifunctional sensor for selective and sensitive detection of vitamin B12 and tartrazine by Förster resonance energy transfer

We used thiamine nitrate (TN) as single material to fabricate nitrogen and sulfur co-doped carbon quantum dots (N,S-CQDs) with a quantum yield of 10.4% through one-pot hydrothermal method, and its properties were characterized by TEM, XPS, FTIR, fluorescence (FL) and UV-vis spectrophotometer, respectively. The fluorescence of N,S-CQDs was effectively quenched in the presence of vitamin B12 (VB12)/tartrazine due to Förster resonance energy transfer (FRET). Moreover, the rate (K_T) and efficiency (E%) of energy transfer from N,S-CQDs (as a donor) to VB12/tartrazine (as an acceptor) enhanced with increasing the concentrations of acceptor, and the K_T and E% were also varied with the change of excitation wavelengths (from 338 to 408 nm). Based on this principle, a multifunctional fluorescence probe was designed for selective and sensitive detection of VB12/tartrazine with a detection limit (3σ/slope) of 15.6/18.0 nmol/L. Meanwhile, the proposed method was successfully employed to detect VB12/tartrazine in milk and several beverages with a recovery range of 97.5-104.2%/91.0-110.6%.

A convenient fluorescent assay for quinolones based on their inhibition towards the oxidase-like activity of Cu2+

This work reports on a novel and convenient fluorescent assay for four quinolones including nalidixic acid, cinoxacin, ciprofloxacin and moxifloxacin, with Cu²⁺-triggered and quinolone-inhibited oxidation of o-phenylenediamine.

Ratiometric fluorescence, solution-phase and filter-paper visualization detection of ciprofloxacin based on dual-emitting carbon dot/silicon dot hybrids

This study demonstrates the ratiometric fluorescence, solution-phase and filter-paper visual detection of ciprofloxacin based on dual-emitting carbon dot/silicon dot hybrids.