Up-and-down-shaker-assisted dispersive liquid-liquid microextraction coupled with gas chromatography-mass spectrometry for the determination of fungicides in wine.

An up-and-down-shaker-assisted dispersive liquid-liquid microextraction (UDSA-DLLME) method coupled with gas chromatography-mass spectrometry was developed for the determination of fungicides (cyprodinil, procymidone, fludioxonil, flusilazole, benalaxyl, and tebuconazole) in wine. The developed method requires 11 µL of 1-octanol without the need for dispersive solvents. The total extraction time was approximately 3 min. Under optimum conditions, the linear range of the method was 0.05-100 µg L(-1) for all fungicides and the limit of detection was 0.007-0.025 µg L(-1). The absolute and relative recoveries were 31-83% and 83-107% for white wine, respectively, and 32-85% and 83-108% for red wine, respectively. The intra-day and inter-day precision were 0.5-7.5% and 0.7-6.1%, respectively. Our developed method had good sensitivity and high extraction efficiency. UDSA-DLLME is a desirable method in terms of performance and speed.

Water with low concentration of surfactant in dispersed solvent-assisted emulsion dispersive liquid-liquid microextraction for the determination of fungicides in wine.

A sample preparation method, dispersive liquid-liquid microextraction assisted by an emulsion with low concentration of a surfactant in water and dispersed solvent coupled with gas chromatography-mass spectrometry, was developed for the analysis of the fungicides cyprodinil, procymidone, fludioxonil, flusilazole, benalaxyl, and tebuconazole in wine. A microsyringe was used to withdraw and discharge a mixture of extraction solvent and 240 µL of an aqueous solution of Triton X-100 (the dispersed agent) four times within 10 s to form a cloudy emulsion in the syringe. This emulsion was then injected into a 5 mL wine sample spiked with all of the above fungicides. The total extraction time was approximately 0.5 min. Under optimum conditions using 1-octanol (12 µL) as extraction solvent, the linear range of the method in analysis of all six fungicides was 0.05-100 µg L(-1), and the limit of detection ranged from 0.013 to 0.155 µg L(-1). The absolute recoveries (n = 3) and relative recoveries (n = 3) were 30-83 and 81-108% for white wine at 0.5, 5, and 5 µg L(-1), and 30-92 and 81-110% for red wine, respectively. The intraday (n = 7) and interday (n = 6) relative standard deviations ranged from 4.4 to 8.8% and from 4.3 to 11.2% at 0.5 µg L(-1), respectively. The method achieved high enrichment factors. It is an alternative sample preparation technique with good performance.

Optimization of two different dispersive liquid-liquid microextraction methods followed by gas chromatography-mass spectrometry determination for polycyclic aromatic hydrocarbons (PAHs) analysis in water.

Novel sample preparation methods termed "up-and-down shaker-assisted dispersive liquid-liquid microextraction (UDSA-DLLME)" and "water with low concentration of surfactant in dispersed solvent-assisted emulsion dispersive liquid-liquid microextraction (WLSEME)" coupled with gas chromatography-mass spectrometry (GC-MS) have been developed for the analysis of 11 polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. For UDSA-DLLME, an up-and-down shaker-assisted emulsification was employed. Extraction was complete in 3min. Only 14 µL of 1-heptanol was required, without a dispersive solvent. Under the optimum conditions, the linear range was 0.08-100 µg L(-1), and the LODs were in the range 0.022-0.060 µg L(-1). The enrichment factors (EFs) ranged from 392 to 766. Relative recoveries were between 84% and 113% for river, lake, and field water. In WLSEME, 9 µL of 1-nonanol as extraction solvent and 240 µL of 1 mg L(-1) Triton X-100 as surfactant were mixed in a microsyringe to form a cloudy emulsified solution, which was then injected into the samples. Compared with other surfactant-assisted emulsion methods, WLSEME uses much less surfactant. The linear range was 0.08-100 µg L(-1), and the LODs were 0.022-0.13 µg L(-1). The EFs ranged from 388 to 649. The relative recoveries were 86-114% for all three water specimens.