Rapid fluorescence spectroscopic screening method for the sensitive detection of thiabendazole in red wine

In this work, a rapid, sensitive, reliable and cost-effective fluorescence spectroscopic method has been established for the detection of thiabendazole (TBZ) in red wine, based on second-derivative constant-wavelength synchronous fluorescence spectroscopy (DCWSFS) coupled with an ultrasound-assisted liquid-liquid extraction technique. The constant wavelength difference (Δλ) was set at 50 nm between the excitation and emission monochromators. Compared with UV-Vis absorption spectroscopy and conventional fluorescence spectroscopy, this method has the advantages of improving spectral resolution and eliminating the interference of spectral background from red wine. This method avoids the requirement for complicated purification and pretreatment procedures. The detection of TBZ is free from the interference of co-existence pesticides, demonstrating the high selectivity of this method. Satisfactory recoveries of the spiked red wine samples were obtained, ranging from 85.9% to 102.8%. The calibration curve showed good linearity in a range from 0.05 to 1.0 μg mL^-1 for TBZ. The detection limit (S/N = 3) was 7.2 ng mL^-1 and the relative standard deviation (n = 5) value was 3.9%. The results obtained by this method for analyzing TBZ in red wine samples correlated well with those obtained by the HPLC method. This method could be an attractive alternative for the rapid screening of TBZ in large amounts of samples.