Deep eutectic solvents based on carboxylic acids for metals separation from plant samples: Elemental analysis by ICP-OES

Element and Water-Soluble Vitamins Profile of Rhus coriaria L. (Sumac) Grown in Different Regions

In this study, the amounts of some elements and water-soluble vitamins in Rhus coriaria L. (Sumac) samples grown in different regions were analyzed by ICP-OES and HPLC, respectively. The maximum amount of Na, K, Mg, and P was determined in the sumac samples of Kadana, Sheladize, Maraş, and Derishke regions, respectively. The richest regions in terms of trace elements such as Zn, Cu, Fe, Se, Mn, Cr, Mo, Ni, and B were Charput, Derishke, Ranya, Charput, Ranya, Derishke, Elazığ, Derishke, and Kadana, respectively. The highest amount of As, Cd, Pb, and Hg in sumac samples were determined in Kadana, Kadana, Trawanish, and Charput regions, respectively, while the lowest amounts were determined in Maraş, Sheladize, Elazig, and Trawanish regions sumac samples. Since target hazard coefficient (THQ) and total target hazard coefficient (TTHQ) values calculated for minor, toxic and heavy metals investigated in sumac samples are well below one; therefore, they do not pose a health risk. From the result obtained, sumac is a good food additive spice in terms of water-soluble vitamins except ascorbic acid. The amounts of ascorbic acid, thiamine, riboflavin, nicotine amide, nicotinic acid, pantothenic acid, pyridoxine, folic acid, and cyanocobalamin in sumac samples varied between 78.90-36.57, 173.57-61.11, 518.4-182.3, 314.0-105.6, 1292.1-788.7, 779.2-301.7, 385.8-133.4, 826.2-473.1, and 192.6-73.9 µg/g dw, respectively. Differences in the amount of elements and water-soluble vitamins among sumac samples from different regions may be due to geographical and ecological reasons.

Supramolecular deep eutectic solvent: a powerful tool for pre-concentration of trace metals in edible oil

The utilization of supramolecular deep eutectic solvent eddy-assisted liquid-liquid microextraction utilizing 2-hydroxypropyl β-cyclodextrin (SUPRADES) has been identified as a successful method for pre-enriching Cu, Zn, and Mn in vegetable oil samples. Determination of each element was conducted by inductively coupled plasma optical emission spectrometry (ICP-OES) after digestion of metal-enriched phases. Various parameters were examined, including the composition of SUPRADES species [2HP-β-CD: DL-lactic acid], a cyclodextrin mass ratio of 20 wt%, a water bath temperature of 75 °C, an extractor volume of 800 μL, a dispersant volume of 50 μL, and an eddy current time of 5 min. Optimal conditions resulted in extraction rates of 99.6% for Cu, 105.2% for Zn, and 101.5% for Mn. The method exhibits a broad linear range spanning from 10 to 20,000 μg L-1, with determination coefficients exceeding 0.99 for all analytes. Enrichment coefficients of 24, 21, and 35 were observed. Limits of detection ranged from 0.89 to 1.30 μg L-1, while limits of quantification ranged from 3.23 to 4.29 μg L-1. The unique structural characteristics of the method enable the successful determination of trace elements in a variety of edible vegetable oils.

Deep eutectic solvents for the determination of endocrine disrupting chemicals

The harmful effects of endocrine disrupting chemicals (EDCs) to humans and other organisms in the environment have been well established over the years, and more studies are ongoing to classify other chemicals that have the potential to alter or disrupt the regular function of the endocrine system. In addition to toxicological studies, analytical detection systems are progressively being improved to facilitate accurate determination of EDCs in biological, environmental and food samples. Recent microextraction methods have focused on the use of green chemicals that are safe for analytical applications, and present very low or no toxicity upon disposal. Deep eutectic solvents (DESs) have emerged as one of the viable alternatives to the conventional hazardous solvents, and their unique properties make them very useful in different applications. Notably, the use of renewable sources to prepare DESs leads to highly biodegradable products that mitigate negative ecological impacts. This review presents an overview of both organic and inorganic EDCs and their ramifications on human health. It also presents the fundamental principles of liquid phase and solid phase microextraction methods, and gives a comprehensive account of the use of DESs for the determination of EDCs in various samples.

Deep eutectic solvent-based ultrasound-assisted extraction in soil samples preparation and elemental determination by ICP-OES

A fast, simple and green method was established for the extraction of Al, Be, Ca, Co, Cr, Cu, Mn, P, Pb, V and Zn from soil samples using ultrasound-assisted deep eutectic solvents (DESs). DESs based on choline chloride, carboxylic acids and polyols were investigated. It was established that the solvent synthesized from choline chloride and oxalic acid provided the highest extraction recovery (85-104%). Inductively coupled plasma-optical emission spectrometry (ICP-OES) was employed to determine the target analytes in the extracts. The parameters that affect the extraction of target analytes was optimized using standard reference samples. Target analytes could be effectively isolated from soil samples using 0.5 g of DES, ultrasound for 40 min, and heating at 80 ℃. The content of the target analytes determined by this method showed no significant difference from the certified values of 24 reference samples. The proposed method was applied to quantify target analytes in real soil samples. Compared to the traditional acid digestion method, this method showed no significant difference in precision and accuracy, with a confidence level of 95%. The proposed method was found to be simple, accurate and environmentally friendly.

Microwave-assisted extraction based on emulsion breaking with natural deep eutectic solvent for vegetable oil sample preparation prior to elemental determination by ICP OES

This study presents a novel and efficient method for the extraction of Al, Ca, Cr, Cu, K, Mg, Mn, and Zn in vegetable oil samples using a Natural Deep Eutectic Solvent (NADES) as an extractor combined with microwave radiation (MW) in an emulsion system. The NADES prepared with choline chloride:oxalic acid:water (1:1:4 molar ratio) provided a high extraction rate using 5.0 mL of the sample, 1.7 mL of NADES, and 1.3 mL of Triton X-100. The optimum conditions were obtained with 36 s of vortexing, 5 min of extraction, and 10 s for emulsion-breaking in MW. Under these conditions, recoveries ranged from 91% to 110% and relative standard deviations <9.0% were obtained. The limit of quantification (mg kg-1) was: 0.018 (Al), 0.032 (Ca), 0.007 (Cr), 0.006 (Cu), 0.013 (K), 0.027 (Mg), 0.002 (Mn), and 0.019 (Zn). The proposed method showed comparable results to reference methods and advantages, such as speed, low cost, and simplicity. The combination of NADES and MW represents a sustainable and innovative approach to the elemental determination composition of vegetable oils and contributes to advances in sample preparation methods.

A hydrophobic deep eutectic solvent-based microextraction for the determination of ultra-trace arsenic in foods by an electrothermal atomization atomic absorption spectrometry

A hydrophobic deep eutectic solvent-based liquid-phase microextraction approach for the determination of ultra-trace arsenic (total) in foods by an electrothermal atomization atomic absorption spectrometry was developed. Various deep eutectic solvents based on tetraoctylammonium bromide and fatty acids (heptanoic, octanoic, nonanoic, decanoic acids) were studied as extraction solvents for preconcentration of arsenic (V) from mineralizates obtained after a microwave digestion of food samples. Phenomenon of ion-pairs formation between dihydroarsenate and precursor of deep eutectic solvent (tetraoctylammonium) and mass-transfer of the ion-pairs into deep eutectic solvent phase was presented for the first time. The proposed approach allowed to preconcentrate analyte into the deep eutectic solvent phase without the use of additional organic solvents (emulsifier agents or dispersive solvent), chelating and reducing agents. It was found, that the deep eutectic solvent based on tetraoctylammonium bromide and heptanoic acid provided more effective preconcentration of analyte from mineralizates (95% extraction recovery, 57-fold enrichment factor). The obtained limit of detection, calculated as a triple signal-to-noise ratio, was 10 ng L-1. The microextraction procedure was applied for the determination of trace arsenic in rice and wheat grains samples.

Facile synthesis of triazolo/benzazolo[2,1-b]quinazolinone derivatives catalyzed by a new deep eutectic mixture based on glucose, pregabalin and urea

In this study, a novel natural deep eutectic solvent was prepared from glucose, pregabalin, and urea. The prepared solvent was identified using a variety of techniques, including Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), differential thermal analysis (DTA), and refractive index measurements (RI). The prepared deep eutectic solvent was then utilized for the one-pot synthesis of quinazolinone derivatives. The yields of the product obtained with and without the catalyst were determined, providing insights into the catalytic efficiency of the system. This protocol offers several advantages, including mild reaction conditions, easy reagent preparation, a green process, short reaction times (2-60 min), high yields (80-99%), and a straightforward procedure with the possibility of catalyst reusability.

Sm/Co Magnetic Materials: A Recycling Strategy Using Modifiable Hydrophobic Deep Eutectic Solvents Based on Trioctylphosphine Oxide

Hydrophobic deep eutectic solvents (HDES) are widely used as extractants. Usually, when preparing HDES, only the extraction ability of one component is taken into account, with the second serving as an "inert" component, whose effect on the extraction process is not taken into account. The present study demonstrates the possibility of controlling the selectivity of a hydrophobic deep eutectic solvent based on trioctylphosphine oxide (TOPO) by varying the substance that acts as a hydrogen bond donor, but which does not have an extractive ability. In the course of the work, the influence of the "inert" component on the physicochemical and extraction properties of HDES was confirmed by experimental, spectroscopic, and also calculation methods. A number of phenols with different structural features were chosen as the HDES' hydrogen bond donors to modify: phenol (Ph), para-tert-butylphenol (PTBP) and thymol (Th). Using the example of separation of the Sm/Co pair, the influence of the structure of a hydrogen bond donor on the extraction ability of a hydrophobic deep eutectic solvent was established, where the degree of extraction of Sm (III) increased in the series Th:TOPO < PTBP:TOPO < Ph:TOPO. HDES based on TOPO and phenols can potentially be used to separate Sm and Co from the process leach solutions generated during the hydrometallurgical processing of waste SmCo magnets.

Determination of major and trace elements in plant samples by inductively coupled plasma optical emission spectrometry with deep eutectic solvent extraction based on choline chloride and carboxylic acids

A rapid, precise, and environmentally friendly approach utilizing an ultrasound assisted deep eutectic solvent-based extraction method was developed for the extraction of Ca, Fe, K, Mg, Mn, Na, P, S and Zn from plant samples. The investigation was conducted on deep eutectic solvents that are based on choline chloride and carboxylic acids. The determination of target analytes in the extracts was carried out using inductively coupled plasma-optical emission spectrometry (ICP-OES). The DESs based on malic acid were found to exhibit the highest extraction recovery values (95-106%). The parameters affecting the extraction of target analytes were optimized using standard reference materials. The target analytes can be effectively extracted from plant samples using 0.5 g of DESs and ultrasonication for 40 minutes. The determination results of the reference samples indicated that the relative error (RE) was below 15.1%, and the relative standard deviation (RSD) was less than 6.3%, demonstrating excellent accuracy and precision. The proposed method was employed to quantify target analytes in actual plant samples. The accuracy of this method was not significantly different from that of the microwave digestion method. The proposed method has been demonstrated to be a valid approach for the determination of target elements in actual plant samples.

A fungal functionalized magnetized solid phase extractor for preconcentrations of Pb(II), Mn(II), and Co(II) from real samples

Due to increasing industrialization and overpopulation, the amount of toxic metals is increasing in the environment, including air, soil, water, and food. Solid phase extraction is an efficient and ideal technique to preconcentrate the toxic metals before their measurements by analytical instruments. Russula brevipes was immobilized on γ-Fe₂O₃ magnetic nanoparticles and employed as a SPE sorbent to preconcentrate the trace level of Pb(II), Mn(II), and Co(II). To investigate the extraction conditions, significant experimental parameters were examined in details. LODs were calculated as 0.022, 0.015, and 0.024 ng mL^-1 for Pb(II), Mn(II), and Co(II), respectively. The biosorption capacities of R. brevipes immobilized γ-Fe₂O₃ were calculated as 43.1 mg g^-1 for Pb(II), 54.9 mg g^-1 for Mn(II), and 49.7 mg g^-1 for Co(II). Pb(II), Mn(II), and Co(II) in food samples at trace levels were preconcentrated by applying the developed method.

Chromium Contamination and Health Risk Assessment of Soil and Agricultural Products in a Rural Area in Southern China

With the rapid development of industry, chromium (Cr) pollutants accumulate constantly in the soil, causing severe soil Cr pollution problems. Farmland Cr pollution hurts the safety of agricultural production and indirectly affects human health and safety. However, the current situation of Cr pollution in farmland soil and crops has not been detailed enough. In this study, the evaluation of Cr potential risk in soil-crop systems was conducted in a rural area that was affected by industry and historic sewage irrigation. Ten different crops and rhizosphere soils were sampled from four fields. The results showed that Cr contents in farmland soil exceeded the national standard threshold in China (>21.85%), and the Cr content in edible parts of some agricultural products exceeded that too. According to the PCA and relation analysis, the Cr accumulation in edible parts showed a significant correlation with soil Cr contents and available potassium contents. Except for water spinach, the target hazard quotient (THQ) of the other crops was lower than 1.0 but the carcinogenic health risks all exceeded the limits. The carcinogenic risks (CR) of different types of crops are food crops > legume crops > leafy vegetable crops and root-tuber crops. A comprehensive assessment revealed that planting water spinach in this area had the highest potential risk of Cr pollution. This study provided a scientific and reliable approach by integrating soil environmental quality and agricultural product security, which helps evaluate the potential risk of Cr in arable land more efficiently and lays technical guidelines for local agricultural production safety.

Improvement of solubility, stability and antioxidant activity of carotenoids using deep eutectic solvent-based microemulsions

Natural carotenoids have been widely used as colorants and antioxidants in process of food, medicine, and cosmetic. However, the carotenoids have low bioactivity in vivo due to poor water-solubility. To enhance the solubility, stability and antioxidant activity of carotenoids, novel microemulsions (MEs) composed with deep eutectic solvents (DESs), tween 80 and water were developed as alternatives to organic solvents. The phase diagrams and physicochemical properties (viscosity, pH, and diameter) of the DES-based MEs were investigated at different temperatures. Then the solubility distribution, storage stability and DPPH free radical-scavenging activity of three carotenoids (astaxanthin, astaxanthin ester and lutein) in the MEs were evaluated. Compared with ethanol, methanol, and acetone, all the DES-based MEs studied significantly enhanced the solubility of the carotenoids due to the stronger hydrogen bonding and Van der Waals interactions. The highest solubilities of 0.27, 473.63, and 12.50 mg/mL for astaxanthin, astaxanthin ester and lutein, respectively, were observed in the MEs containing DES (DL-menthol:acetic acid = 1:2) at 35 ℃. Moreover, astaxanthin ester can be well preserved in the MEs containing DES (DL-menthol:octanoic acid = 1:2) with a half-life of more than 69 days. In addition, the DPPH scavenging capacities of the three carotenoids in all the MEs were higher than the organic solvents. The results revealed that the DES-based MEs with low viscosity (<0.2 Pa•s) and mild acidic pH (4-5) are potential solvents for natural carotenoids in food processing and storage, medicine making, as well as biomaterials processing.