Chujun Liu,Yawen Guo,Bo Wang,Lan Chen,Kaizhou Xie,Chenggen Yang
A simple and sensitive gas chromatography–tandem mass spectrometry (GC–MS/MS) method was established for the quantitative screening of penicillin G residues in chicken and duck eggs (whole egg, yolk and albumen). The analyte was separated on a TG-1MS capillary column (30.0 m × 0.25 mm i.d., 0.25 μm) with an external calibration method and electron impact (EI) ionization. Samples were pretreated using an accelerated solvent extraction (ASE) procedure followed by solid-phase extraction (SPE) on HLB cartridges (60 mg/3 mL). The derivative, which was safer and easier to store than penicillin G, was obtained by reacting trimethylsilyl diazomethane (TMSD) with penicillin G. The method was validated by the following parameters: linearity, accuracy, precision, limit of detection (LOD) and limit of quantification (LOQ). The matrix-matched calibration curves had good linearity (R2 ≥ 0.9994) within the concentration range of LOQ–200.0 µg/kg for penicillin G in the sample matrices. In the same concentration range, the accuracy, in terms of recovery, was 80.31–94.50%; the relative standard deviation (RSD), intra-day RSD and inter-day RSD ranged from 1.24 to 3.44%, 2.13 to 4.82% and 2.74 to 6.13%, respectively. The LODs and LOQs of penicillin G in the matrices were in the ranges of 1.70–3.20 and 6.10–8.50 μg/kg, respectively. The applicability of the GC–MS/MS method was demonstrated by the determination of poultry eggs obtained from local markets with no penicillin G residues.Keywords:penicillin G;GC–MS/MS;ASE;poultry eggs;SPE
Based on the aggregation-induced emission effect triggered by Al 3+ , a novel probe was constructed for the ratiometric fluorescence visualization detection of fluoroquinolones (FQs) residues. In this probe, Al 3+ cased the glutathione-modified copper nanoclusters (GSH-CuNCs) to aggregate by the interaction with surface carboxyl groups, restricting the intramolecular vibration and rotation of GSH-CuNCs and reducing the non-radiative relaxation of excited states. Significant enhancement of fluorescence and quantum yield were achieved. In the presence of FQs, Al 3+ /GSH-CuNCs coordinated with FQs to form a polymer that inhibited intramolecular proton transfer in the excited state of FQs, thereby enhancing the intrinsic fluorescence of FQs, while the fluorescence intensity of Al 3+ /GSH-CuNCs was not disturbed. The probe solution changed from red to blue (or green) under UV lamp as the concentration of FQs increased, providing the possibility for semi-quantitative visual analysis. It also showed sensitive spectral responses to FQs with detection limits of 7.9 (ciprofloxacin), 6.8 (gatifloxacin), and 9.5 nM (enrofloxacin), respectively. The application potential in the detection of FQs residues in poultry eggs was verified by real sample test. Additionally, the probe has been extended to the development of fluorescent test paper and the smartphone detection platform, contributing to rapid, portable, visual quantitative analysis of FQs.
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