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A cloud-point extraction (CPE) method using Triton X-114 (TX-114) nonionic surfactant was developed for the extraction and preconcentration of propyl gallate (PG), tertiary butyl hydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) from edible oils. The optimum conditions of CPE were 2.5% (v/v) TX-114, 0.5% (w/v) NaCl and 40 min equilibration time at 50 °C. The surfactant-rich phase was then analyzed by reversed-phase high-performance liquid chromatography with ultraviolet detection at 280 nm, using a gradient mobile phase consisting of methanol and 1.5% (v/v) acetic acid. Under the studied conditions, 4 synthetic phenolic antioxidants (SPAs) were successfully separated within 24 min. The limits of detection (LOD) were 1.9 ng mL(-1) for PG, 11 ng mL(-1) for TBHQ, 2.3 ng mL(-1) for BHA, and 5.9 ng mL(-1) for BHT. Recoveries of the SPAs spiked into edible oil were in the range 81% to 88%. The CPE method was shown to be potentially useful for the preconcentration of the target analytes, with a preconcentration factor of 14. Moreover, the method is simple, has high sensitivity, consumes much less solvent than traditional methods, and is environment-friendly. Practical Application: The method established in this article uses less organic solvent to extract SPAs from edible oils; it is simple, highly sensitive and results in no pollution to the environment.

A simple and sensitive spectrofluorimetric method was developed for the determination of four fluoroquinolone antibacterials namely norfloxacin (NOR), ofloxacin (OFL), ciprofloxacin (CIP) and gatifloxacin (GAT) in honey through charge transfer (CT) complex formation with 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), and then the inclusion complexes of FQs-DDQ with β-cyclodextrin (β-CD) were formed, which resulted in drastic fluorescence enhancement. The effect of several parameters including the concentration of reactants, reaction temperature, time and ultrasonic treatment on the efficiency of the proposed method involving CT reaction and inclusion interaction was systematically investigated. Under the optimum conditions, the limits of detection (LODs) for four FQs in honey varied from 11.6 to 15.4 μg/kg (signal-to-noise ratio (S/N) = 3). The intra- and interday relative standard deviations (RSDs) were 1.6-4.0 % (n = 5) for four FQs. The calibration graph was linear from 42.8 to 1346.8 μg/kg with correlation coefficients not less than 0.9905. The recoveries of four FQs at three different spiked concentrations in honey samples ranged from 80.9 % to 92.8 %. The results indicated that the method was successfully applied for analyzing FQs in honey.

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