scholarly journals Application of Deep Eutectic Solvents and Ionic Liquids in the Extraction of Catechins from Tea

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3216 ◽  
Author(s):  
Sylwia Bajkacz ◽  
Jakub Adamek ◽  
Anna Sobska
Keyword(s):  
Ionic Liquids ◽  
Solid Phase ◽  
Choline Chloride ◽  
Deep Eutectic Solvents ◽  
Mixing Ratios ◽  
Good Solubility ◽  
Tea Infusions ◽  
Girard’S Reagent ◽  
Spe Method

This work aimed to comprehensively evaluate the potential and effectiveness of deep eutectic solvents (DESs) in the extraction of seven catechins from various tea samples. Different combinations of DES were used, consisting of Girard’s reagent T (GrT) in various mixing ratios with organic acids and choline chloride. The yields of the DES extractions were compared with those from ionic liquids and conventional solvent. DES contained malic acid, as the hydrogen bond donors showed a good solubility of catechins with different polarities. In the second part of the study, a solid-phase extraction (SPE) method was applied to the extraction of catechins from tea infusions. The method was applied to the determination of selected catechins in tea leaves and tea infusions. Furthermore, we demonstrated that the proposed procedure works well in the simultaneous monitoring of these polyphenols, which makes it a useful tool in the quality control of tea.

scholarly journals Purification of Curcuminoids from Natural Deep Eutectic Solvents (NADES) Matrices Using Chromatography-Based Separation Methods

2021 ◽  
Vol 21 (4) ◽  
pp. 806
Author(s):  
Orchidea Rachmaniah ◽  
Muhammad Rifqy Muhsin ◽  
Angga Widya Putra ◽  
Muhammad Rachimoellah
Keyword(s):  
Acetic Acid ◽  
Solid Phase ◽  
Choline Chloride ◽  
Deep Eutectic Solvents ◽  
Extraction Process ◽  
Acid Water ◽  
Molar Ratio ◽  
Separation And Purification ◽  
Natural Deep Eutectic Solvents ◽  
Spe Method

Curcuminoids can be successfully extracted from Curcuma zedoaria using natural deep eutectic solvents (NADES) as extraction solvents. However, a mixture of extracted curcuminoids, NADES, and impurities from C. zedoaria was obtained as a slurry at the end of the extraction process. Therefore, further separation and purification were required to obtain the extracted compound in high purity. Herein, two purification methods based on classical column chromatography (CCC) and solid-phase extraction (SPE), were evaluated for the purification of curcuminoids from NADES matrices after extraction. Choline chloride–malic acid–water (CCMA–H2O) and choline chloride–citric acid–water (CCCA–H2O) in the molar ratio of 1:1:18 were selected as NADES matrices due to their high solubility and stabilization capability for curcuminoids. Ethanol-conditioned silica gel (60–200 µm) was applied as the bed resin for CCC, and a C18 cartridge was used for SPE. Acetonitrile/0.1% acetic acid, water/0.1% acetic acid, and iso-propanol/0.1% acetic acid were used as mobile phases for CCC. For SPE, methanol/0.05% acetic acid and water/0.05% acetic acid were applied in the conditioning step, water/0.05% acetic acid in the washing step, and methanol/acetonitrile (1:1) in the eluting step. The SPE method produced higher recovery of curcuminoids from the CCCA–H2O and CCMA–H2O matrices (75.27% and 73.40%, respectively) compared to CCC (51.9% and 61.0%, respectively). After removing the NADES constituents from the crude extract of curcuminoids, recrystallization was attempted.

scholarly journals A Review of the electrochemical corrosion of metals in choline chloride based deep eutectic solvents

2021 ◽  
Author(s):  
Mihael Bučko ◽  
Jelena Bajat
Keyword(s):  
Ionic Liquids ◽  
Corrosion Rate ◽  
Wide Spectrum ◽  
Choline Chloride ◽  
Electrochemical Corrosion ◽  
Deep Eutectic Solvents ◽  
High Viscosity ◽  
Metal Corrosion ◽  
Melting Points ◽  
Separate Class

Deep eutectic solvents (DESs) are a class of mixtures with melting points notably lower than those of their raw constituent components. These liquids have found a tremendously wide spectrum of applications in the last two decades of their research, so their contact and interaction with technical metals and alloys are inevitable. Therefore, the corrosivity of DESs towards metals is an extremely important topic. This review summarizes research efforts collected in the last two decades related to the corrosion rate of various metals in different DESs. Since the DESs are mainly composed of organic raw compounds, and by their physicochemical properties they may be regarded as a separate class of ionic liquids, the literature data about DESs corrosivity has been compared to the data related to the corrosivity of various organic solvents and ionic liquids as well. All the results gained until now show significantly low corrosivity of DESs. This observation is discussed in relation to the chemical composition of DESs. The absence of the oxidizing agents, the inhibitory action of organic ions and molecules, high viscosity and low electrical conductivity have been recognized as the main factors contributing to the low metal corrosion rate in DESs.

scholarly journals Determination of dimethoate, 2,4-dichlorophenoxy acetic acid, mecoprop and linuron pesticides in environmental waters in Republic of Macedonia by high performance liquid chromatography

2008 ◽  
Vol 27 (1) ◽  
pp. 25 ◽  
Author(s):  
Aleksandra Nestorovska-Krsteska ◽  
Meri Mirčeska ◽  
Jean-Jacques Aaron ◽  
Zoran Zdravkovski
Keyword(s):  
Acetic Acid ◽  
Solid Phase Extraction ◽  
High Performance ◽  
Solid Phase ◽  
Sampling Period ◽  
Phase Extraction ◽  
Environmental Waters ◽  
Spe Method ◽  
Dichlorophenoxy Acetic Acid

An HPLC-UVDAD method for determination of dimethoate, 2,4-dichlorophenoxy acetic acid (2,4-D), mecoprop (MCPP) and linuron in environmental waters was developed. The water samples were concentrated and extracted by a solid phase extraction (SPE) method on Bond Elut PPL cartridges. After extraction the investigated compounds were separated on Stability RP Pesticides chromatographic column using mobile phase composed of acetonitrile- water-acetic acid in volume fractions of 39:59:2 and flow rate of 0.7 mL/min. Ultraviolet absorption detection was carried out for dimethoate, 2,4-D and MCPP at 229 nm, and for linuron at 249 nm. Recoveries made from 500 mL of drinking waters using solid phase extraction ranged between 64.3–92.1 %. The method was applied to environmental waters in Macedonia that receive runoffs from agriculture lands. The levels of pesticides under study ranged between 0.31 μg/L and 7.05 μg/L, depending on the compound and sampling period.

scholarly journals Highly Efficient Extraction Procedures Based on Natural Deep Eutectic Solvents or Ionic Liquids for Determination of 20-Hydroxyecdysone in Spinach

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4736
Author(s):  
Sylwia Bajkacz ◽  
Kornelia Rusin ◽  
Anna Wolny ◽  
Jakub Adamek ◽  
Karol Erfurt ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Extraction Procedure ◽  
Deep Eutectic Solvents ◽  
Molar Ratio ◽  
Green Extraction ◽  
Natural Deep Eutectic Solvents ◽  
Efficient Extraction ◽  
Solid Liquid ◽  
Extraction Agent

A novel, efficient extraction procedure based on natural deep eutectic solvents (NADES) and ionic liquids (ILs) for determination of 20-hydroxyecdysone (20-E) in spinach has been developed. NADES, the first green extraction agent, with different hydrogen bond donors and acceptors are screened in order to determine extraction efficiencies. NADES consisting of lactic acid and levulinic acid at a molar ratio of 1:1 exhibits the highest yields. ILs, the second green extraction agent, with various cations and anions are also investigated, where [TEA] [OAc]·AcOH, χAcOH = 0.75 displays the highest recovery. Moreover, NADES-SLE and IL-SLE (SLE, solid-liquid extraction) parameters are investigated. Using the obtained optimized method, the recoveries of the target compound in spinach are above 93% and 88% for NADES-SLE and IL-SLE procedure, respectively. The methods display good linearity within the range of 0.5–30 μg/g and LODs of 0.17 µg/g. The proposed NADES-SLE-UHPLC-UV and IL-SLE-UHPLC-UV procedures can be applied to the analysis of 20-E in real spinach samples, making it a potentially promising technique for food matrix. The main advantage of this study is the superior efficiency of the new, green extraction solvents, which results in a significant reduction of extraction time and solvents as compared to those in the literature.

scholarly journals Development of a Solid-Phase Extraction Method for Determination of Pheophorbide a and Pyropheophorbide a in Health Foods by Liquid Chromatography

2004 ◽  
Vol 87 (4) ◽  
pp. 937-942 ◽  
Author(s):  
Harumi Oshima ◽  
Eiji Ueno ◽  
Isao Saito ◽  
Hiroshi Matsumoto
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Reversed Phase ◽  
Official Method ◽  
Phase Extraction ◽  
Pheophorbide A ◽  
Significant Difference ◽  
Spe Method

Abstract A simple solid-phase extraction (SPE) method was developed for the liquid chromatography (LC) determination of pheophorbide (Phor) a and pyropheophorbide (Pyro) a in health foods such as chlorella, spirulina, etc. The food sample was extracted with 85% (v/v) acetone. The extract was acidified with hydrochloric acid and loaded on a C18 cartridge. After washing with water, Phor a and Pyro a were eluted with the LC mobile phase. Phor a and Pyro a were separated by isocratic reversed-phase LC and quantitated by fluorescence detection. The recoveries for spiked samples of chlorella and the extract were 87.1–102.0%. Commercial health foods (chlorella, spirulina, aloe, kale, Jews mallow, and green tea leaves) were analyzed using the SPE method. The values found for Phor a and Pyro a ranged from 2 to 788 μg/g and from <1 to 24 μg/g, respectively. There was no significant difference between the SPE method and the official method in Japan (spectrophotometry after liquid–liquid extraction). The advantages of the SPE method are the short extraction times, lack of emulsions, and reduced consumption of organic solvents compared with the official method in Japan. The SPE method is considered to be useful for the screening of Phor a and Pyro a in health foods.

scholarly journals Determination of Organic Acids in Salicornia herbacea by Solid-phase Extraction Combined with Liquid Chromatography

2013 ◽  
Vol 8 (2) ◽  
pp. 1934578X1300800
Author(s):  
Damian Han ◽  
Minglei Tian ◽  
Dong Wha Park ◽  
Kyung Ho Row
Keyword(s):  
Solid Phase Extraction ◽  
Ferulic Acid ◽  
Caffeic Acid ◽  
Solid Phase ◽  
Phase Extraction ◽  
Relative Standard ◽  
Trifluoracetic Acid ◽  
Spe Method ◽  
Salicornia Herbacea

A solid-phase extraction (SPE) method for the determination of procatechuic acid, ferulic acid and caffeic acid in Salicornia herbacea L. (Hamcho) has been developed. The optimal conditions were obtained by using a C18 SPE cartridge. By using ethanol and acetonitrile /water/ trifluoracetic acid as washing and eluting solvents, most interfering compounds originating from the hamcho matrix were eliminated. The extracts were sufficiently clean to be directly injected into the HPLC for further chromatographic analysis. Good linearity was obtained from 0.1 to 200 μg/mL (r > 0.999) for procatechuic acid, 0.2 to 400 μg/mL (r > 0.999) for caffeic acid and 0.3 to 600 μg/mL (r > 0.999) for ferulic acid, with the relative standard deviations being less than 3.6%. The mean recoveries of procatechuic acid, ferulic acid and caffeic acid from hamcho were more than 79.2% and the detection limit (S/N = 3:1) was 0.02 μg/mL for procatechuic acid, 0.01 μg/mL for caffeic acid and 0.04 μg/mL for ferulic acid. This method is a viable alternative to the existing HPLC methods for analyzing the content of procatechuic acid, ferulic acid and caffeic acid in hamcho.

scholarly journals Reduction of the Coefficient of Friction of Steel-Steel Tribological Contacts by Novel Graphene-Deep Eutectic Solvents (DESs) Lubricants

Lubricants ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 37 ◽  
Author(s):  
Ignacio Garcia ◽  
Silvia Guerra ◽  
Juan de Damborenea ◽  
Ana Conde
Keyword(s):  
Mechanical Properties ◽  
Ionic Liquids ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Adhesive Wear ◽  
Choline Chloride ◽  
Deep Eutectic Solvents ◽  
The Other ◽  
Graphene Flakes ◽  
The Coefficient Of Friction

Deep eutectic ionic liquids (DES) possess similar properties to conventional ionic liquids (ILs). However, ILs cannot be considered as environmentally friendly compounds due to both its processing and synthesis, which could have significant polluting effects. On the contrary, deep eutectic solvents (DESs) can be biodegradable, non-toxic, and have a lower price than most ILs, making them potentially useful in a wide variety of advanced technological applications, such as tribology. On the other hand, graphene has recently been proposed as an extremely promising lubricant due to its combination of mechanical properties and chemical stability as well as its “green” character. In the present paper, graphene flakes (≈250 nm) have been used as an additive to DES composed of choline chloride (ChCl)-urea, ChCl-ethylene glycol, and ChCl-malic acid. According to the results, the addition of 1 wt% graphene reduces friction coefficient (COF) and, notably, prevents adhesive wear, reducing wear rate on steel-steel sliding contacts.

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