Determination of Multiclass Antibiotics in Fish Muscle Using a QuEChERS-UHPLC-MS/MS Method.

The surging global demand for fish has increased aquaculture practices, where antibiotics have become indispensable to prevent diseases. However, the passive incorporation of these compounds into the diet may have adverse effects on human health. In this work, the QuEChERS method combined with ultra-high-performance liquid chromatography tandem mass spectrometry was applied for the determination of 10 multiclass antibiotics (5 quinolones, 2 sulfonamides, 2 diaminopyrimidines, and 1 macrolide) in muscle tissue of farmed fish (European sea bass and gilt-head sea bream). The applied method demonstrated acceptable recovery values, mostly between 70 and 120%, with limits of quantification of the method meeting the established EU maximum residue limits. The analysis of twenty fish samples in duplicate revealed that most antibiotics were not present, with the only exception of oxolinic acid and tilmicosin in European sea bass, which were below the limit of quantification of the method.

Insights into emerging organic pollutants extraction from polypropylene, polystyrene, and polyethylene microplastics.

BACKGROUND: Microplastics have the capability of retaining contaminants on their surface, increasing their persistence, preconcentrating them, and acting as transport vectors. Nevertheless, the determination of these compounds in plastic matrices poses several analytical issues and challenges, including the capability of many of these methods of only determining the extractable pollutants fractions, repeatability issues, etc. In this sense, it is primordial to evaluate the effect of the critical parameters that allow to obtain a quantitative extraction of the target analytes from microplastics, including the matrix effect of each of the studied polymers, the influence of particle size, and the effect of weathering. RESULTS: A simple and effective methodology for the extraction of 17 emerging organic pollutants from both pristine (polypropylene, polystyrene, and low- and high-density polyethylene) and weathered (polypropylene and polyethylene) microplastics has been developed, optimized, and validated, achieving recovery values of 70-120 % and low method quantification limits (9.2-35.5 ng/g). Results show the importance of cryomilling microplastics (as smaller particle sizes improve recovery and homogenization), something ignored in most publications. The differences in matrix effect for the studied pristine polymers highlights the importance of treating polymers individually, without extrapolating results. In weathered microplastics, matrix effect is overall higher than in their pristine counterparts, evidencing the necessity of always carrying out matrix effect and recovery studies in environmental microplastics. The analysis of 10 samples collected in Playa Grande (Tenerife, Canary Islands, Spain) revealed quantitative amounts of bisphenol A (10.8 ± 3.4 ng/g) in one of them. SIGNIFICANCE: For the first time, the effect of particle size, weathering and matrix effect have been simultaneously evaluated on microplastics, revealing the importance of their assessment to properly validate the methodology. Additionally, the method shows good performance in all the different polymers and has been successfully applied to the analysis of environmental samples of microplastics.

Sorption of levonorgestrel on polyethylene, polystyrene and polypropylene microplastics.

Sorption studies involving microplastics (MPs) are essential to understand the mechanisms implicated in contaminant retention. In this research, a complete study of the sorption behaviour of a hormonal contraceptive -levonorgestrel- in MPs of different composition in two distinct matrices was performed, using high-performance liquid chromatography coupled to a UV detector for the determination of levonorgestrel. Characterization of the studied MPs was achieved by X-ray diffraction, differential scanning calorimetry, and Fourier-transformed infrared spectroscopy. Kinetic and isotherm studies were performed using a batch design under controlled conditions: 500 mg of MPs pellets of 3-5 mm diameter, agitation at 125 rpm, and 30 °C. The comparison of results in ultrapure water and artificial seawater, revealed changes in sorption capacity, and the predominant sorption mechanisms involved. Overall, all studied MPs showed sorption affinity towards levonorgestrel, being low-density polyethylene the one with the highest sorption capacity in ultrapure water and polystyrene in seawater.

Extraction of Emerging Contaminants from Environmental Waters and Urine by Dispersive Liquid-Liquid Microextraction with Solidification of the Floating Organic Droplet Using Fenchol:Acetic Acid Deep Eutectic Mixtures.

In this work, several eutectic mixtures formed by fenchol and acetic acid at seven molar ratios (between 4:1 and 1:4) were characterized and studied for the first time for their possible application as extraction solvents in dispersive liquid-liquid microextraction based on the solidification of the floating organic droplet (DLLME-SFO). A group of 13 emerging contaminants (gemfibrozil, bisphenol F, bisphenol A, 17ß-estradiol, testosterone, estrone, levonorgestrel, 4-tert-octylphenol, butyl benzyl phthalate, dibutyl phthalate, 4-octylphenol, 4-nonylphenol, and dihexyl phthalate) was selected and determined by liquid chromatography with ultraviolet and tandem mass spectrometry detection. Among the studied mixtures, only those of 2:1 and 1:1 provided the suitable features from an operational and repeatability point of view, suggesting that several eutectic mixtures of the same components may also provide similar results. Once the extraction conditions of both mixtures were optimized, the method was applied to the extraction of sea water, urine, and wastewater at different concentration levels, allowing the achievement of absolute recovery values between 49 and 100% for most analytes with relative standard deviation values below 19%. In addition, several samples of each type were analyzed, finding bisphenol A and gemfibrozil in some of them. The greenness of the method was also evaluated using the AGREEprep metric. The DLLME-SFO procedure was found to be very simple, quick, and effective and with a good sample throughput.

Miniaturized green sample preparation approaches for pharmaceutical analysis.

The development of green sample preparation procedures is an extremely important research field in which more and more applications are constantly being proposed in different areas, including pharmaceutical analysis. This review article is aimed at providing a general overview of the development of miniaturized green analytical sample preparation procedures in the pharmaceutical analysis field, with special focus on the works published between January 2017 and July 2021. Particular attention has been paid to the application of environmentally friendly solvents and sorbents as well as nanomaterials or high extraction capacity sorbents in which the solvent volumes and reagents amounts are drastically reduced, with their subsequent advantages from the sustainability point of view.

Extraction of phthalic acid esters from soft drinks and infusions by dispersive liquid-liquid microextraction based on the solidification of the floating organic drop using a menthol-based natural deep eutectic solvent.

In this work, a natural deep eutectic solvent (NADES) consisting of L-menthol and acetic acid in a 1:1 molar ratio has been applied as extraction solvent for the dispersive liquid-liquid microextraction based on the solidification of the floating organic drop (DLLME-SFO) of a group of nine phthalic acid esters (dipropyl phthalate, DPP; butyl benzyl phthalate, BBP; dibutyl phthalate, DBP; dicyclohexyl phthalate, DCHP; diisopentyl phthalate, DIPP; di-n-pentyl phthalate, DNPP; di(2-ethylhexyl) phthalate, DEHP; diisononyl phthalate, DINP; and diisodecyl phthalate, DIDP) from three common infusions (camomile, pennyroyal mint, and linden teas) and three soft drinks (green tea, tonic, and lime and lemon drink), using dihexyl phthalate (DHP) and di-n-octyl phthalate (DNOP) as internal standards. After the DLLME-SFO procedure, analyses were carried out by high-performance liquid chromatography with UV detection. Method calibration showed good linearity for all the analytes and matrices, with determination coefficients (R2) higher than 0.9910. Relative recovery values were between 71 and 125 %, with relative standard deviation values in the range 1-22 % for the six types of samples, while the limits of quantification of the method were in the range 4.3-51.1 µg/L for infusions and in the range 3.5-33.3 µg/L for soft drinks. Several samples purchased in different local supermarkets were analysed, finding DPP, DBP, DIPP, DEHP and DINP, although only DPP, DBP and DEHP could be quantified in some of them.

Covalent Organic Frameworks in Sample Preparation.

Covalent organic frameworks (COFs) can be classified as emerging porous crystalline polymers with extremely high porosity and surface area size, and good thermal stability. These properties have awakened the interests of many areas, opening new horizons of research and applications. In the Analytical Chemistry field, COFs have found an important application in sample preparation approaches since their inherent properties clearly match, in a good number of cases, with the ideal characteristics of any extraction or clean-up sorbent. The review article is meant to provide a detailed overview of the different COFs that have been used up to now for sample preparation (i.e., solid-phase extraction in its most relevant operational modes-conventional, dispersive, magnetic/solid-phase microextraction and stir-bar sorptive extraction); the extraction devices/formats in which they have been applied; and their performances and suitability for this task.

Analysis of phthalic acid esters in sea water and sea sand using polymer-coated magnetic nanoparticles as extraction sorbent.

In this work, poly(dopamine)-coated magnetic nanoparticles (Fe3O4@pDA) have been used as sorbents for the magnetic dispersive solid-phase extraction (m-dSPE) of a group of 10 phthalic acid esters (dipropyl phthalate, DPP, dibutyl phthalate, DBP, dicyclohexyl phthalate, DCHP, bis(2-ethylhexyl)phthalate, DEHP, di-n-octyl phthalate, DNOP, diisodecyl phthalate, DIDP, butylbenzyl phthalate, BBP, diisononyl phthalate, DINP, diisopentyl phthalate, DIPP, di-n-pentyl phthalate, DNPP) and one adipate (di(2-ethylhexyl) adipate, DEHA) from sea water and sea sand extracts employing DBP-d4 and DHP-d4 as internal standards. After m-dSPE, analysis was carried out by gas chromatography mass spectrometry. Mean recovery values (which were determined at three concentration levels) ranged between 70 and 120%, with relative standard deviation values ≤ 20%, for nearly all analytes in both matrices. Matrix-matched calibration curves revealed the presence of matrix effects for certain PAEs, specially for sea sand, though linearity was assayed with determination coefficients (R2) above 0.991 for all target analytes. The limits of quantification of the method were in the range 1.8-319 ng/L for sea water and 0.020-4.0 ng/g for sea sand. Several samples of each type collected at different sites of the coast of Tenerife were also analysed. Only DEHA, DNOP and DIPP were detected in some of the sea sand samples at concentrations ≤ 44 ng/g.