Microwave assisted extraction combined with dispersive liquid–liquid microextraction as a sensitive sample preparation method for the determination of haloanisoles and halophenols in cork stoppers and oak barrel sawdust

Acid induced dispersive liquid-liquid microextraction based on in situ formation of hydrophobic deep eutectic solvents for the extraction of bisphenol A and alkylphenols in water and beverage samples

This study describes the development of an acid induced dispersive liquid-liquid microextraction method based on the in situ formation of hydrophobic deep eutectic solvents for the extraction of bisphenol A and alkylphenols from environmental water and beverage samples. Hydrochloric acid altered the hydrophilic-hydrophobic state of fatty acid salts to obtain hydrophobic fatty acids, which formed hydrophobic deep eutectic solvents with analytes in situ to extract the analytes. Under optimized conditions, the limits of detection and limits of quantitation were 0.03-0.1 μg L-1 and 0.12-0.3 μg L-1, the intraday and interday relative standard deviations were less than 3.9 %, and the enrichment factor was 29-32. The recoveries of bisphenol A and alkylphenols were 95.9-104.9 % and 86.9-105.0 %, respectively. The extraction process used only hydrochloric acid and fatty acid salts, and the extraction process required less than 1 min. This method has the advantages of simplicity, speed, low cost and environmental friendliness.

Extraction of diazinon, haloxyfop-R-methyl, hexaconazole, diniconazole, and triticonazole in cheese samples using a ferrofluid based liquid phase extraction method prior to gas chromatography

In the present study, a ternary phase solvent extraction combined with dispersive liquid-liquid microextraction was developed for the extraction of diazinon, haloxyfop-R-methyl, hexaconazole, diniconazole, and triticonazole from cheese samples. The extracted analytes were determined using gas chromatography. In this work, first, the analytes were extracted into an organic phase and then enriched using a dispersive liquid-liquid microextraction. Deep eutectic solvent-based ferrofluid was synthesized and used as an extraction solvent in the dispersive liquid-liquid microextraction step, which makes the method fast and green. After optimization of experimental conditions, under the best extraction conditions, limits of detection and quantification were found in the ranges of 0.18-0.39 and 0.6-1.3 ng g-1, respectively. Enrichment factors and extraction recoveries of the analytes ranged from 138-156 and 69-78%, respectively. In the end, the proposed method was successfully applied to assess the studied pesticides in cheese samples.

Reversed-phase dispersive liquid-liquid microextraction based on decomposition of deep eutectic solvent for the determination of lead and cadmium in vegetable oil

In this work, a reversed-phase dispersive liquid-liquid microextraction procedure based on the decomposition of deep eutectic solvent was suggested for the first time. The procedure was utilized for fast and simple separation of lead and cadmium from vegetable oil samples. The procedure assumed mixing of oil sample and DES based on menthol, formic acid and water. Water as component of DES promoted its decomposition in sample matrix resulting menthol dissolution in the sample phase and dispersion of aqueous formic acid solution. In this procedure menthol acted as a dispersive solvent during DES decomposition for dispersion of aqueous formic acid solution. The metals were determined by the square-wave anodic stripping voltammetry. The limits of detection, were 0.01 µg kg^-1 for lead and 0.006 µg kg^-1 for cadmium. The RSD was less then 6% for both analytes. The enrichment factor was 36 and 39 for lead and cadmium, respectively.

Headspace solid-phase microextraction coupled to gas chromatography-tandem mass spectrometry for the determination of haloanisoles in sparkling (cava and cider) and non-sparkling (wine) alcoholic beverages

A highly sensitive analytical method was developed to determine 2,4,6-trichloroanisole (TCA), 2,3,4,6-tetrachloroanisole (TeCA), 2,4,6-tribromoanisole (TBA) and 2,3,4,5,6-pentachloroanisole (PCA) in sparkling alcoholic beverages. The method was based on the use of headspace solid-phase microextraction (HS-SPME) using a polydimethylsiloxane (PDMS) fibre. It was coupled to gas chromatography-triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS) for the detection and quantification of the target haloanisoles. The method was fully automated and no sample preparation was needed. The method was validated for alcoholic beverages. The influence of CO₂ on the extraction efficiency was also evaluated for the studied sparkling drinks (cava and cider). All the calibration curves showed good linearity (R² > 0.98) within the tested range (1-50 ng l^-1). Recoveries were evaluated at three different levels (1, 5 and 50 ng l^-1) and were always between 71% and 119%. Precision was expressed as relative standard deviation (RSD), and was evaluated as intra- and inter-day precisions, with values ≤ 22% in both cases. Limits of quantitation (LOQs) were ≤ 0.91 ng l^-1, which are below the sensory threshold levels for such compounds in humans. The validated method was applied to commercial samples, 10 cavas and 10 ciders, but it was also used for the analysis of nine red wines and four white wines, demonstrating the further applicability of the proposed method to non-sparkling beverages. TCA was detected in most samples at up to 0.45 ng l^-1.

Microwave assisted extraction combined with solvent bar microextraction for one-step solvent-minimized extraction, cleanup and preconcentration of polycyclic aromatic hydrocarbons in soil samples

For the first time, a novel one-step sample preparation method that combines microwave assisted extraction and solvent bar microextraction (MAE-SBME) with analysis by gas chromatography-mass spectrometry (GC-MS), was developed for the fast and efficient determination of polycyclic aromatic hydrocarbons (PAHs) in environmental soil samples. An interesting feature of the new procedure is that SBME was conducted simultaneously with MAE. Thus, the extract from the SBME could be directly and immediately analyzed by GC-MS. A separate clean up and/or preconcentration process, such as time-consuming and tedious gel permeation chromatography, solid-phase extraction, filtration, or adsorption chromatography, normally associated with conventional MAE, was not necessary. It is also notable that the procedure was environmentally benign since water was used as the extraction solvent in MAE, and only several microliters of organic solvent were used in SBME. Some factors affecting the extraction were studied and optimized. Under the most favorable conditions, the method showed good linearities (between 0.2 and 500, 0.5 and 500, 1 and 500, and 2 and 500 ng/g, depending on the analytes), low limits of detection (from 0.03 to 0.25 ng/g), and satisfactory precision (with relative standard deviations below 9.8%). The MAE-SBME procedure provides a fast and simple sample preparation approach for the processing of environmental soil samples.