| dc.description.abstract | In this study, a sensitive, simple and environmental−friendly method for the determination of eight Benzotriazoles (BTRs) and Benzothiazoles (BTHs) derivatives in tea beverages was developed. The target analytes were extracted from tea beverages using deep eutectic solvent−based ultrasound−assisted liquid−liquid microextraction (DES−USALLME). DESs are a group of novel “green” solvents, and the benefits of DESs include: starting materials are affordable, can be easily prepared at room temperature, have low or negligible toxicity, and can be tuned for hydrophobic or hydrophilic organic analytes. A hydrophobic DES was used in this study, which based on the mixture of choline chloride (as a hydrogen bond acceptor) and 4−chlorophenol (as a hydrogen bond donor) at molar ratio of 1 : 3. The determination of target analytes was performed by the combination of ultrahigh− performance liquid chromatography quadrupole time−of−flight mass spectrometry (UHPLC−QTOF−MS).
The parameters of DES−USALLME were screened and optimized by multivariate experimental design base on Multilevel categoric design and Face-centered Central Composite Design plus with response surface design and analysis of variance (ANOVA), respectively. For Multilevel categoric design screening, the optimal selections were: molar ratio of DES was 1 : 3, the extraction mechanical force was ultrasonication, and no required ice bath after ultrasonication. Then, the optimal conditions for Face-centered Central Composite Design were: 800 μL of DES, and sonicated for 5 mins in ultrasonic bath at 55 ℃. After optimization, the method was validated and shown to possess low limits of quantification (LOQs) ranging from 0.15 to 20 ng/mL, high precisions (less than 16%) for both inter-day and intra-day analysis. The developed method was then successfully applied for the analysis of some selected BTRs and BTHs in tea beverages. | en_US |