The incessant effort to perform a more sustainable chemistry has brought about the development of new materials that accomplish the principles of the green chemistry. In this context, deep eutectic ...solvents (DESs) have surged as one of the most promising alternatives to the use of toxic organic solvents. Their unique properties have led to a huge development of these materials and a sharp increase of their applications in the recent years in analytical chemistry. They have been applied in sample preparation and analytical techniques. The quantity of new information generated from studies associated with DESs is enormous and needs to be continuously revised. In this review, the most relevant aspects related to the application of DESs in the last five years (2016–2020) have been compiled and critically discussed in order to provide a global view about the advantages and limitations of these new materials in the area of analytical chemistry.
•DESs characteristics make them ideal as green materials in analytical chemistry.•Different DESs (NADESs, THEDESs and polyDESs) have been used in analytical chemistry.•DESs have been used in sorbent-based and solvent-based sample preparation procedures.•DESs have been used in chromatographic and electrophoretic techniques.•Further studies are needed to understand synthesis and action mechanisms of DESs.
QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was initially developed by Anastassiades and coworkers as an interesting alternative based on the main principles of the Green ...Chemistry to the determination of pesticides in fruits and vegetables. However, the great versatility of the procedure has allowed its application in other types of matrices and analytes with excellent results. In fact, nowadays the main advantages of QuEChERS such as the effective elimination of matrix effect as well as obtain a high recovery of target analytes are extensively known in diverse fields such as food, environmental and biological analysis. This review article pretends to provide an overview of the most relevant applications of the QuEChERS method in the last five years in these three different areas as well as the main trends regarding of the development and evolution of this sample preparation protocol.
•QuEChERS method is one of the most applied methods for the analysis of pesticides.•It has been applied for the extraction of a large variety of analytes and matrices.•Numerous modifications have been carried out to improve method performance.•The method has been mainly combined with LC-MS and GC-MS.
The separation of 11 phthalic acid ester (PAEs) was carried out by nano‐liquid chromatography coupled to ultraviolet and MS detection. Preliminary experiments were achieved in order to select ...suitable stationary phases and chromatographic conditions. The baseline separation was obtained, for all compounds, with an XBridgeTM C18 column in less than 15 min, working in step gradient mode. The sensitivity of the method was improved by on‐column focusing. PAEs were extracted from alcoholic and nonalcoholic beverages using vortex‐assisted emulsification dispersive liquid–liquid microextration and natural deep eutectic solvents. The whole method was validated in terms of linearity, sensitivity, precision, recovery, and repeatability. Combination of both off‐line sample preparation preconcentration and large injection volume led to obtain LOQs in the range 5–47 ng/mL. The developed nano‐LC‐UV method was extended to MS detection to confirm the presence of PAEs in some beverages commercialized in different types of packaging.
The recovery of nitrogen and phosphorus is important to promote circular economy in wastewater treatment plants (WWTPs). In this study, the life cycle assessment (LCA) and techno-economic assessment ...(TEA) of a novel pilot-scale plant aimed at recovering ammonium nitrate and struvite for subsequent application in agriculture was conducted. The nutrient recovery scheme was implemented in the sludge line of the WWTP and included (i) struvite crystallisation and (ii) ion-exchange process combined with gas permeable membrane contactor. The LCA showed that using a fertilizer solution containing the recovered nutrients was environmentally better in most of the impact categories evaluated. Ammonium nitrate was the most important environmental contributor when using the recovered fertilizer solution as a result of the high consumption of chemicals needed for its production. The TEA illustrated that the implementation of the nutrient recovery scheme in the WWTP featured a negative net present value (NPV), primarily attributed to the high consumption of chemicals (representing 30 % of the gross cost). However, the implementation of the nutrient recovery scheme in the WWTP could be economically favourable if the cost of ammonium nitrate and struvite increased to 0.68 and 0.58 €/kg, respectively. The results of this pilot-scale study highlight that nutrient recovery considering the whole value chain for fertilizer application can be an attractive full-scale alternative from a sustainability point of view.
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•Life cycle assessment and economic evaluation for nutrient recovery were conducted.•Agricultural application of the recovered fertilizers was environmentally better.•Nutrient recovery scheme implementation in a WWTP was not economically favourable.•Chemicals' consumption is the most important environmental and economic contributor.•Ammonium nitrate and struvite costs of 0.68 and 0.58 €/kg improve the economics.
Nitrogen (N) is a macronutrient that, together with P and K, is vital for improving agricultural yields, but its excessive use in crop fertilisation and presence in treated wastewater and sludge are ...generating emissions both into the atmosphere and into natural water bodies, which leads to eutrophication events. The Haber–Bosch process is energy-intensive and it is the main chemical route to produce reactive nitrogen for the production of fertilisers. Furthermore, there is a strong dependence on imports of reactive nitrogen in Spain and Europe. For these reasons, it is necessary to propose sustainable alternatives that allow solving environmental and supply problems, in addition to proposing efficient management schemes that fit into the circular economy approach. In this context, a nitrogen flow analysis (NFA) was carried out for Spain with the year 2016 as reference. To assess some interactions and flows of N, specific sub-models were also considered for the agriculture and waste management systems. For the food and non-food flow systems, country-specific data were considered. The sectors covered were crop production (CP), animal production (AP), food processing (FP), non-food production (NF) and human consumption (HC). The results reveal a total annual import of 2142 kt N/y, of which 43 % accumulated in stocks of soils and water bodies (913 kt N/y). The largest proportion of losses was associated with emissions from agriculture (724 kt N/y to water bodies and 132 kt N/y accumulated in soils), followed by industry emissions to the atmosphere (122 kt N/y). Wastewater treatment plants (WWTPs) received around 67 kt N/y, of which 26 % was removed as biosolids and 20 % of these biosolids were recovered to be used for fertilising applications. The 49 kt N/y discharged in the final treated effluent represented 79 % of the total loss of reactive nitrogen to water bodies. In addition, an analysis of N-use efficiency and the actions required for its improvement in Spain, as well as the impact of the current diet on the N cycle, was carried out.
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•A nitrogen flow analysis was carried out for Spain with the year 2016 as reference.•The largest proportion of losses was associated with air emissions from agriculture and industry.•Results highlight the dependence on products with high N content from third markets.•The efficiency of N use and the impact of current diet on N cycling have been evaluated.•A circular strategy involves recovering the nutrients present in WW and transforming them into fertilisers.
•-m-NPs were applied as sorbent for the m-μ-dSPE of PAEs from environmental samples.•-UHPLC-QqQ-MS/MS was used for target analytes determination.•-Recovery values were in the range 70–120 % and LOQs ...between 6 and 178 ng/L.•Real samples were evaluated finding DMP, DPP, BBP, DIBP, DBP in some of them.
In this work, the suitability of Fe3O4 nanoparticles coated with reduced-graphene oxide as sorbent was evaluated for the extraction of a group of fourteen phthalic acid esters (i.e. benzylbutyl phthalate (BBP), bis-2-n-butoxyethyl phthalate (DBEP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), dicyclohexyl phthalate (DCHP), bis-2-ethoxyethyl phthalate (DEEP), diisodecyl phthalate (DIDP), diisononyl phthalate (DINP), bis-isopentyl phthalate (DIPP), bis-(2-methoxyethyl) phthalate (DMEP), dimethyl phthalate (DMP), di-n-octyl phthalate (DNOP), bis-n-pentyl phthalate (DNPP), dipropyl phthalate (DPP)) from environmental samples. Extraction was carried out using magnetic-micro dispersive solid-phase extraction while separation, identification and quantification of the target analytes were achieved by ultra-high-performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry. The methodology was validated for three different types of water samples using dibutyl phthalate-3,4,5,6-d4 as internal standard for all of them. Recovery values ranged from 70 to 120% for the three matrices with relative standard deviation values lower than 20%. Limits of quantification of the method achieved were in the range 6–178 ng/L for all samples and analytes. The methodology was applied for the evaluation of real samples finding the presence of DMP, DPP, BBP, DIBP and DBP in some of the analysed matrices.
A new green alternative vortex-assisted dispersive liquid–liquid microextraction method based on a natural hydrophobic deep eutectic solvent was developed for the extraction of 14 phthalic acid ...esters and one adipate in cold infusions and tonic waters. Analyses were carried out using ultra-performance liquid chromatography coupled to tandem mass spectrometry. Different eutectic mixtures based on the monoterpene thymol (essential oil of thyme) and medium-chain fatty acids (octanoic and decanoic acids) at different molar ratios were tested in this regard. The effect of different factors affecting extraction efficiency was optimized through a systematic approach. The method was validated by means of precision, matrix-matched calibration, recovery, and repeatability studies using two different deuterated surrogate standards (dibutyl phthalate-3,4,5,6-d 4 and dihexyl phthalate-3,4,5,6-d 4). The method proved to be linear (determination coefficients were higher than 0.9912) with normalized recoveries in the range between 71 and 124% (except for di-n-octyl phthalate at a low concentration level in tonic water 63%). Then, the method was applied for the analysis of the selected compounds in 3 pineapple/green tea-based cold infusions and 8 tonic beverages. Finally, the greenness of the procedure was assessed using the Analytical Eco-Scale. This paper represents the first application of this natural hydrophobic deep eutectic solvent for the analysis of phthalate esters, and, also the first time, these compounds are analyzed in cold infusion and tonic water.
•A ChCl:phenol based deep eutectic solvent was applied for the DLLME of phthalates.•Parameters affecting the extraction efficiency of DLLME were studied and optimised.•DLLME-HPLC-DAD method was ...validated for different kinds of beverages.•Commercially available products were analysed using the developed methodology.•Positive samples were confirmed by UHPLC-MS/MS analysis.
In this work, a green, inexpensive, simple and fast deep eutectic solvent (DES)-based dispersive liquid–liquid microextraction was evaluated, for the first time, for the extraction of phthalates (i.e. benzylbutyl phthalate, diisobutyl phthalate, diisopentyl phthalate, di-n-pentyl phthalate, di-(2-ethylhexyl) phthalate, di-n-octyl phthalate, diisononyl phthalate, diisodecyl phthalate) from different beverages. Separation and determination were achieved by high performance liquid chromatography-diode-array detection while confirmation was carried out by tandem mass spectrometry. The main factors affecting the extraction such as type and volume of DES and emulsifier, pH and ionic strength, were optimised. Choline chloride:phenol-based DES showed the best results. The methodology was validated for tea, apple-based beverage and pineapple juice. Recovery values ranged from 84 to 120% with relative standard deviation values lower than 11%. Limits of detection of the method were in the range 5.1–14.2 µg L−1 for tea, 5.3–17.8 µg L−1 for apple beverages and 5.9–15.6 µg L−1 for pineapple juices.
•Endocrine disruptors were analyzed in bottled water, kombucha and water kefir.•Alkylphenols, bisphenols and alkylphenol ethoxylates were simultaneously determined.•A NaHDES was applied for the ...vortex-assisted DLLME.•Factors affecting the extraction efficiency were optimized by an univariate protocol.•UHPLC-MS system was employed for separation and determination of target analytes.
In this work, the analysis of alkylphenols, bisphenols and alkylphenol ethoxylates in bottled waters, kombuchas and water kefir was performed through a vortex-assisted dispersive liquid–liquid microextraction method based on a natural hydrophobic eutectic solvent. For this purpose, mixtures of monoterpenes and fatty acids were employed. Different factors affecting extraction were optimized and the method was validated in terms of matrix effect, linearity, limits of detection and recovery. Recovery values varied between 70.0 and 124.3% (except for 4-tert-butylphenol: 67.0% and 4-n-nonylphenol: 60.8% in water kefir) and limits of detection were in the range 0.10 ng/L – 2.99 µg/L. Finally, 8 bottled waters, 8 kombuchas and 4 water kefirs were analyzed and 4-tert-octylphenol monoethoxylate was detected in water (20.28 ± 0.99 – 62.08 ± 3.63 µg/L). This is the first application analyzing xenobiotic contaminants in kombucha and water kefir and the first time in which the three types of compounds are simultaneously extracted by dispersive liquid–liquid microextraction.
A non-ionic hydrophobic natural deep eutectic solvent (HNADES) based on thymol and menthol was proposed for the liquid-liquid microextraction of fourteen phthalates and one adipate from environmental ...water samples. Separation, identification, and quantification were achieved by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. The main factors affecting the extraction efficiency were thoroughly studied. Sample pH of 8 and 100 μL of thymol:menthol at molar ratio 2:1 were selected as the best conditions, while ionic strength and type of dispersant solvent were not relevant for the extraction of the target compounds. The whole methodology was validated for treated wastewater, runoff, and pond water matrices, using di-
n
-butyl phthalate-3,4,5,6-d
4
and dihexyl phthalate-3,4,5,6-d
4
as surrogates. Recovery ranged from 70 to 127% with relative standard deviation values lower than 14%. Limits of quantification of the method were in the range 0.042–0.425 μg/L for treated wastewater, 0.015–0.386 μg/L for runoff, and 0.013–0.376 μg/L for pond water. The methodology was applied for the analysis of real treated wastewater, runoff, and pond water samples from different places of Tenerife and Gran Canaria (Canary Islands) finding the presence of diethyl phthalate, diallyl phthalate, dipropyl phthalate, benzylbutyl phthalate, di-n-butyl phthalate, bis-(2-
n
-butoxyethyl) phthalate, di-n-pentyl phthalate, dicyclohexyl phthalate, and bis-(2-ethylhexyl) phthalate at concentrations between 105.2 and 3414 ng/L.
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