Determination of DDT in honey samples by liquid-liquid extraction with low-temperature purification (LLE-LTP) combined to HPLC-DAD.

Flavonoids are polyphenol compounds that are widely distributed in honey; they play an important role in its antioxidant activity and aid in distinguishing various species of honey. An analytical method based on solid phase extraction and high performance liquid chromatography with tandem mass spectrometry (SPE-HPLC-MS/MS) for the simultaneous determination of rutin, myricetin, morin, quercetin, naringenin, hesperetin, luteolin, genistein, kaempferol, isorhamnetin, apigenin, pinocembrin, wogonin, chrysin, galangin, genkwanin, and ferulic acid in honey was developed and validated. The honey samples were diluted with HCl solution (pH 2) and cleaned up on a C18 column by solid phase extraction; the methanol eluent was filtered through a nylon membrane and analyzed by LC-MS/MS on an ODS-3 column (150 mm×4.6 mm, 3 μm). Quantitative detection was performed by LC-MS/MS in the multiple reaction monitoring (MRM) mode under negative electrospray ionization (ESI-) conditions. The external standard method was used for quantitation. The method validation data were obtained. The calibration standard curve solutions were prepared by honey matrix-matching; the linear range was 0-200 μg/kg, with correlation coefficients of the calibration standard curves greater than 0.997. The limits of quantification (LOQs) of this method were 20 μg/kg. The recoveries were in the range of 64.5%-113%, and the relative standard deviations were 1.4%-14.5% at three spiked levels (20, 40, and 100 μg/kg). The developed method is convenient, rapid, and effective, and it is suitable for the determination and confirmation of flavonoids in honey samples.

In this work, an ultrasonic-assisted surfactant/ionic liquid aqueous two-phase system (ATPS) extraction method was developed to extract six tetracycline antibiotics from food samples before their chromatographic determination using high performance liquid chromatography. The ATPS was formed with 1-allyl-3-methyl-imidazolium bromide, Triton X-100, and dipotassium hydrogen phosphate. The parameters including type and amount of surfactant, ionic liquid and salt, pH of sample solution, and sonication time were optimized. Under the optimized conditions, linear calibration curves of the six tetracyclines were obtained in the range of 10--500 $\mu $g L$^{-1}$ with $>$ r$^{2} =$ 0.990 (n $=$ 9). The proposed green analytical extraction method was applied to the analysis of tetracycline antibiotics in milk and honey samples with recovery of 50%--110% and 68%--117%, respectively.

Chapter eleven - Analysis of volatile organic compounds in honey using gas chromatography and mass spectrometry

Correction: Cold-induced Homogenous Liquid–Liquid Extraction Performed in a Refrigerated Centrifuge Combined with Deep Eutectic Solvent-based Dispersive Liquid–Liquid Microextraction for the Extraction of Some Endocrine Disrupting Compounds and Hydroxymethylfurfural from Honey Samples

Miniaturized salting-out liquid–liquid extraction in a coupled-syringe system combined with HPLC–UV for extraction and determination of sulfanilamide

In this study, solid-phase extraction combined with dispersive liquid–liquid microextraction is presented for the simultaneous determination of trace amounts of deltamethrin and permethrin in honey by gas chromatography–mass spectrometry. First, permethrin and deltamethrin were extracted from polluted honey samples by ultrasound-assisted liquid–liquid extraction followed by solid-phase extraction (SPE). Then, the analytes were eluted from the SPE cartridge. The elution solvent containing trace amounts of analytes was applied in dispersive liquid–liquid microextraction (DLLME) step as disperser solvent for further purification and preconcentration of deltamethrin and permethrin. The important parameters such as the type and volume of the solvent for initial extraction of pesticides from honey matrix, the amount of honey, and type and volume of extraction solvent and elution solvent (disperser solvent) were investigated through the process. Under the optimal conditions, good linearity in the range of 0.2–800 ng g−1 with the correlation coefficient (r 2) >0.9986 and 0.9990, low limits of detection (LODs) of 0.02 and 0.04 ng g−1, enrichment factors of 4955 and 4925, and relative standard deviations (RSD%, n = 7) of 1.8 and 2 % were obtained for permethrin and deltamethrin, respectively. The proposed procedure showed satisfactory results for simultaneous determination of deltamethrin and permethrin in honey. Relative recoveries of 94–99.2 % were obtained for real sample analysis.