Search

The use of natural dyes as photosensitizers has several advantages including their easy extraction and their biodegradable, nontoxic, and environmentally friendly nature, which makes them vital for application in dye-sensitized solar cells (DSSC). In the present work, we study the effects of extraction solvent on the photovoltaic performance of a natural dye sensitizer for TiO2-based DSSC. Extracts of Tecoma stans flowers in two different solvents, ethanol and ethanol–water mixture, were used as the dye sensitizer for extending the spectral sensitivity of TiO2. The optical properties of the dye extracts were studied by their UV–visible absorption spectra. Fourier transform infrared spectra revealed the presence of anchoring groups and coloring pigments, and nuclear magnetic resonance spectroscopy and mass spectrometry were used to characterize the main constituents of the dye extract. The photovoltaic characteristics of these dye extracts coated on TiO2 were investigated by employing them as DSSC photoanodes. With the dye extracted in ethanol and coated on TiO2, an open-circuit voltage (Voc) of 0.293 V, short-circuit photocurrent density (Jsc) of 0.790 mA/cm2, fill factor (FF) of 0.46, and conversion efficiency (η) of 0.13% were obtained, whereas dye extracted in the ethanol–water mixture revealed Voc of 0.285 V, Jsc of 0.735 mA/cm2, FF of 0.37, and η of 0.09%. The photovoltaic performance of the dye extracts in the two cases underlines the greater effectiveness of ethanol as dye extraction solvent. [ABSTRACT FROM AUTHOR]

Copyright of Food Technology & Biotechnology is the property of Food Technology & Biotechnology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of the current research was to assess the optimal extraction conditions with respect to ethanol concentration and time to recover betalains from red beetroot (Beta vulgaris L.). Purposely, betalains were extracted from beetroot using water and ethanol based solvent modules at three different time intervals i.e., 20, 40 and 60 min and the obtained extracts were analyzed for betacyanins, betaxanthins and total betalains. The obtained data was further analyzed using three level-two factor central composite design using response surface methodology. The data was fitted to second order polynomial equation by applying multiple regression analysis. The optimal conditions were obtained using maximum desirability function that found to be 31.03, 45.01 and 35.34% aqueous ethanol for betacyanins, betaxanthins and total betalains, respectively whilst, optimum extraction time was recorded to be around 43 min. The experimental values were close to the predicted values that proves the adequacy of the model employed. It was suggested that aqueous-ethanol is suitable for maximal recovery of beetroot betalains instead of ethanol or water as a sole solvent. [ABSTRACT FROM AUTHOR]

Diazinon poisoning is an important issue in occupational, clinical, and forensic toxicology. While sensitive and specific enough to analyse diazinon in biological samples, current methods are time-consuming and too expensive for routine analysis. The aim of this study was therefore to design and validate a simple dispersive liquid-liquid microextraction (DLLME) for the preparation of urine samples to be analysed for diazinon with high performance liquid chromatography with diode-array detector (HPLC-DAD) to establish diazinon exposure and poisoning. To do that, we first identified critical parameters (type and volume of extraction and disperser solvents, pH, surfactant, and salt concentrations) in preliminary experiments and then used central composite design to determine the best experimental conditions for DLLME-HPLC-DAD. For DLLME they were 800 µL of methanol (disperser solvent) and 310 µL of toluene (extraction solvent) injected to the urine sample rapidly via a syringe. The sample was injected into a HPLC-DAD (C18 column, 250×4.6 mm, 5 μm), and the mobile phase was a mixture of acetonitrile and buffer (63:37 v/v, pH 3.2; flow rate: 1 mL/ min). Standard calibration curves for diazinon were linear with the concentration range of 0.5–4 µg/mL, yielding a regression equation Y=0.254X+0.006 with a correlation coefficient of 0.993. The limit of detection and limit of quantification for diazinon were 0.15 µg/mL and 0.45 µg/mL, respectively. The proposed method was accurate, precise, sensitive, and linear over a wide range of diazinon concentrations in urine samples. This method can be employed for diazinon analysis in routine clinical and forensic toxicology settings. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Unique intracellular metabolome of C. carboxidivorans fermenting CO was identified. • Substantial amounts of fatty acids accumulate in the cells as they ferment CO. • WiPM is the best solvent for extraction of metabolites in C. carboxidivorans. Clostridium carboxidivorans ferments CO, CO 2 , and H 2 via the Wood-Ljungdahl pathway. CO, CO 2, and H 2 are unique substrates, unlike other carbon sources like glucose, so it is necessary to analyze intracellular metabolite profiles for gas fermentation by C. carboxidivorans for metabolic engineering. Moreover, it is necessary to optimize the metabolite extraction solvent specifically for C. carboxidivorans fermenting syngas. In comparison with glucose media, the gas media allowed significant abundance changes of 38 and 34 metabolites in the exponential and stationary phases, respectively. Especially, C. carboxidivorans cultivated in the gas media showed changes of fatty acid metabolism and higher levels of intracellular fatty acid synthesis possibly due to cofactor imbalance and slow metabolism. Meanwhile, the evaluation of extraction solvents revealed the mixture of water-isopropanol-methanol (2:2:5, v/v/v) to be the best extraction solvent, which showed a higher extraction capability and reproducibility than pure methanol, the conventional extraction solvent. This is the first metabolomic study to demonstrate the unique intracellular metabolite profiles of the gas fermentation compared to glucose fermentation, and to evaluate water-isopropanol-methanol as the optimal metabolite extraction solvent for C. carboxidivorans on gas fermentation. [ABSTRACT FROM AUTHOR]

Coffee shells were hydrothermally liquefied under FeCl 3 catalysis to produce crude bio-oils at temperatures ranging from 190 to 300 °C. This study investigated the impact of operational parameters (hydrothermal temperature, residence time, Fe3+ catalyst concentration, extraction solvents) on the bio-oil yield. Optimized hydrothermal conditions resulted in a conversion rate of 68.47 % for coffee shells, leading to an 11.51 % yield of light bio-oil extracted from the aqueous phase and a 35.99 % yield of heavy bio-oil from the solid phase. The chemical composition and distillate distribution of the bio-oil were determined through organic element analysis, GC-MS analysis, and TG/DTG analysis. The light bio-oil primarily consisted of furfural derivatives and phenolic derivatives; however, it only accounted for approximately 14.50 % of the total energy recovered from the feedstock. The components present in heavy bio-oils varied depending on the extraction solvents used but mainly comprised fatty acids and their derivatives. Acetone extraction yielded the highest amount of bio-oil; however, its high O/C ratio reduced its higher heating value (HHV). Ethanol extraction also resulted in higher yields but TG/DTG analysis indicated that these fractions contained more refractory volatiles and solid residues compared to other solvents used for extraction. In comparison, n-hexane extraction had a lower yield than both previous methods but offered a lower O/C ratio and higher HHV instead. Our study demonstrated that Fe-catalyzed hydrothermal liquefaction is an efficient method for obtaining value-added compounds and hydrocarbon fuels from coffee shells. [Display omitted] • Coffee shells are hydrothermally liquefied to produce bio-oils under Fe-catalysis. • HTL results in 36.0 wt% heavy bio-oil and 11.5 wt% light bio-oil yields. • The bio-oil extracted by n-hexane has higher hydrocarbon content and HHV. [ABSTRACT FROM AUTHOR]

BACKGROUND: Herbs are rich in various beneficial bioactive compounds and they can be used for many different purposes. One of the most common is maceration of herbs in alcohol. Different substances respond differently to extraction in prepared solutions. It is very important to enhance the highest proportion of beneficial ingredients during the maceration process in a herbal liqueur. A comparative analysis of numerous different phenolic compounds from eight of the most frequently used herbs for making aperitifs in Europe was performed. RESULTS: In the comparison among all studied herbs, the highest phenolic content was found with Artemisia absinthium (wormwood) (14.61 mg g−1) and Mentha piperita (peppermint) (13.89 mg g−1), while the lowest content was found with Centaurium erythraea (common centaury) (3.96 mg g−1). Salvianolic acid isomers and caffeic acid derivatives were the greatest contributors to the total phenolic content in lemon balm, wormwood, peppermint, fennel and sage. These compounds contain more hydroxyl groups and they were better extracted at the beginning of the maceration process. Caraway and common centaury contain more flavonols (quercetin and kaempferol derivatives), with higher chemical stability and fewer hydroxyl groups in their structure. CONCLUSION: The compositions of eight herbal liqueurs were highly related to the presence of different herbal ingredients and their solubility in the extract over time. Most flavonol derivatives were extracted over a longer time and the two liqueurs (common centaury and caraway) therefore had the highest phenolic contents after 3 weeks of maceration. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Chopped pepper, a traditionally fermented condiment product in China, is widely consumed because of its good flavor. However, large amounts of byproduct, namely, chopped pepper seeds (CPS) are produced annually during the manufacture of chopped pepper product, and this material is generally classified as solid waste, which causes waste of resource. In this work, the total phenolics (TPC) and capsaicinoids content, antioxidant property, and α-glucosidase inhibitory activity (GIA) of three varieties CPS (i.e., WPS, LPS, and BRPS) were assessed. The effects of solvents with different polarities, including 80% methanol, 80% acetone, and 80% ethanol, in extracting the bioactive compounds were also investigated. The results indicated that the studied CPS were rich in total phenolics and capsaicinoids with contents of 3,934-6,208 µg GAE/g dw and 1,052-3,692 µg/g dw, respectively. Three capsaicinoid compounds, namely, capsaicin, dihydrocapsaicin, and nordihydrocapsaicin, in the CPS were identified and quantified by HPLC. All CPS samples exhibited potent antioxidant property and GIA. Moreover, the different extraction solvents exhibited considerable influence on TPC, capsaicinoid content, antioxidant capacity, and GIA. Regardless of different polarities extraction solvents, BRPS had the highest level of phenolics, capsaicin, dihydrocapsaicin and nordihydrocapsaicin and exhibited the strongest antioxidant activity and GIA among the three varieties CPS studied. In practical applications, the use of 80% ethanol is recommended for the extraction of bioactive compounds from BRPS, because it is environment friendly. Positive correlations between phenolics, capsaicinoids, antioxidant activity, and GIA were observed by PCA and linear correlation analysis. Thus, CPS, especially BRPS, is abundant and can be a cheap source of natural antioxidants and anti-diabetic compounds, making it an interesting ingredient in the potential future development of nutraceuticals or functional food products and bringing great advantages for food and pharmaceutical industries, consumers, and producers. [ABSTRACT FROM AUTHOR]

This study evaluated the antioxidant activity and total phenolic content (TPC) of Butia odorata fruit extracted with different solvents, as well as the phenolic composition using UHPLC-MS/MS analysis. In addition, the antitumor potential of B. odorata fruit against various cancer cell lines (Caco-2, HeLa, SiHa, C33a) was evaluated for the first time. The TPC and antioxidant activity (DPPH• and ORAC assays) varied according to the extraction solvents, with the highest values obtained for the methanol:water (80:20, v/v) extracts. Thirteen phenolic compounds were quantified in the ethanol:water (80:20, v/v) extracts of B. odorata fruit by UHPLC-MS/MS, with the main compounds identified as (+)-catechin (259 ± 18 mg kg−1), (−)-epicatechin (211 ± 12 mg kg−1) and rutin (161 ± 2 mg kg−1). Sinapic and ellagic acids, trans-resveratrol, naringenin, and apigenin were reported in B. odarata fruit for the first time. Furthermore, the B. odorata fruit showed antitumor activity against cervical cancer cell lines (SiHa and C33a), providing preliminary evidence for further assessment of its anticancer potential. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agronomica Sinica is the property of Crop Science Society of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Coleus forskohlii roots are mainly used for extraction of the bioactive diterpenoid, forskolin, which has enormous biological activities. In this study, impact of the solvent and extraction method on forskolin content from Coleus forskohlii root powder was investigated. Nine solvents from different polarity group were tested for forskolin extraction. It was found that the efficiency of the solvents used to extract forskolin varied considerably (0.18 to 2.91 %). The average values indicated that among all the extractives, forskolin content was significantly higher in methanol (2.91 %), followed by ethanol (2.59 %), and least content was found in water (0.18 %). Low polarity solvents were not found very effective for forskolin extraction. Further three different extraction methods (Soxhlet/refluxing, ultrasound and microwaveassisted solvent extraction) were also compared using safest and most effective solvent for forskolin yield. As ethanol exhibited good extraction efficiency for forskolin and is a safe solvent, it was chosen for further optimization of extraction method. Soxhlet extraction technique gave higher yield of forskolin (0.17 to 2.83 %) compared to microwave-assisted solvent extraction (0.09 to 2.29 %) and ultra sound-assisted extraction (0.08 to 1.47 %). From these results it was evident that the extraction of forskolin depended on extraction process as well as the solvent useds. [ABSTRACT FROM AUTHOR]

Propolis tincture is an extracted form of raw propolis with an extraction solvent, which can be used against several diseases and makes it a possible nutraceutical. Raw propolis is often the objective of geographical identification by its element content. It is harder to identify tinctures, because different production processes may influence the mineral content. Therefore the effect of the extraction time (1 h, 1 day, 1 week and 1 month) and the ethanol content (0, 50, 80 and 100% (v/v)) was checked and recorded based on the element content of the tinctures. The 33 elements were classified into 3 groups by their behaviour. Most of the elements dissolved better in water than in ethanol-content solvents. Essential elements were extracted well also in up to 80% (v/v) ethanol content solvents. The concentration of most of the elements did not change greatly after 1 week. Geographical identification can be applied to the tinctures by their element content. • Extraction process of raw propolis highly affects the element content of tinctures. • Most of the elements were dissolved better in aqueous solutions from raw propolis. • Essential elements with some exceptions were extracted well in up to 80% ethanol. • A one week extraction time was enough to extract most of the elements. [ABSTRACT FROM AUTHOR]

• Pretreatment procedures are optimized for HPLC-MS/MS detection of isoprenoids. • The first report on releasing algal isoprenoids by NaOH for quantitative analysis. • Isoprenoids are depleted by carotenogenesis while accumulated in the dark. Isoprenoid diphosphates are important precursors actively participating in many downstream metabolisms; they are often in modified forms, e.g. , protein-coupled or esterified form. Therefore, in vivo level of free isoprenoid diphosphates is quite low, ˜0.07 nmol/g fresh weight in plants. In order to directly measure the isoprenoid diphosphate pool during stress-induced accumulation of astaxanthin in Haematococcus pluvialis , the present study optimized several pretreatment procedures to enrich free isoprenoid diphosphates for high-pressure liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) detection. Specifically, different extraction solvents, e.g. , water, methanol, chloroform, and mixture of water, methanol, and chloroform (1:1:1, V/V/V), and solid phase extraction (SPE) columns (OASIS@ WAX and HLB Cartridges) were compared; and gentle decoupling by NaOH or trifluoroacetic acid (TFA) was introduced to release free isoprenoid diphosphates. Results found that solvent mixture of water, methanol and chloroform (1:1:1, V/V/V) showed the highest extraction efficiency (R E) for five isoprenoid diphosphates, ranging from 76.83% to 92.43%; HLB column showed the balanced recoveries ranging from 75.29% to 87.54%; and incubation with low NaOH (˜4.7 mmol/L) at 4 °C significantly increased detectable isoprenoid diphosphates in algal cells, some of which were undetectable or in trace level before NaOH decoupling. The method was applied to H. pluvialis cells under various stresses. Low levels of isoprenoid diphosphates were determined in most of the stresses used, e.g. , 0.19 ± 0.09 to 0.98 ± 0.06 mg/g fresh weight (FW) for IPP/DMAPP, 0.35 ± 0.07 mg/g FW for GGPP and undetectable for FPP and GPP; while isoprenoid diphosphates were significantly accumulated in the dark to 3.27 ± 0.05, 0.17 ± 0.09, 1.81 ± 0.16 and 0.58 ± 0.07 mg/g FW for IPP/DMAPP, GPP, FPP and GGPP, respectively. These results implied that isoprenoid diphosphates were exhausted by downstream carotenogenesis under stress. Our work emphasizes NaOH decoupling for exact quantitation of in vivo isoprenoid diphosphates. [ABSTRACT FROM AUTHOR]

Highlights • Development of HPTLC method for the determination of quinalphos in human whole blood. • Optimization of extraction procedure. • Recovery of 93.61% was achieved from diethyl ether extract at pH 3. • Bioanalytical method validation of HPTLC method. • Application of developed procedure in three fatal cases of poisoning. Abstract A simple and rapid procedure for the determination of quinalphos in human whole blood using liquid-liquid extraction and high-performance thin-layer chromatography was developed and validated. Seven different organic solvents were tested for optimum extraction of quinalphos from spiked blood samples. The effect of pH on the extraction yield of quinalphos was also examined. An average recovery of 93.61% was achieved from diethyl ether solvent at pH 3. Chromatographic separation was performed on silica gel 60F 254 plates using mobile phase n -hexane-acetone in the ration 9:1 (v/v). Densitometric detection was carried out at 325 nm in absorbance mode. The interference of other organophosphorus pesticides of forensic relevance was not observed. The linear regression analysis in spiked whole blood samples resulted in linear calibration plot in the range 1 to 100 μg mL–1 with r2 = 0.9981. Sensitivity was represented by LLOQ at 1 μg mL–1. The within-day precision and between-day precision ranged from 0.18 to 1.04%, and 0.14 to 0.79% with an overall average recovery of 91.06% at three concentrations 1, 10, and 50 μg mL–1. No significant decrease in the concentration of quinalphos was observed for samples under different storage conditions. Finally, the developed procedure was applied to postmortem blood samples obtained in three fatal cases of poisoning by quinalphos. [ABSTRACT FROM AUTHOR]

Antioxidant activity, total phenolic content (TPC), total flavonoids, carotenoids, pH, and total titratable acidity of red and black date's vinegar were analyzed. The extraction method was designed and optimized for this purpose with respect to the variety and solvent concentrations along with the time of ultrasonication. The results showed that red dates' vinegar has significantly (p < 0.05) higher total phenols (3.38 ± 0.13 mg GAE/ml) and antioxidant activity as compared to black dates' vinegar, which had a higher amount of carotenoids (3.43 ± 0.11 mg/100 ml). Similarly, red dates' vinegar has more flavonoids as compared to commercially available Zhenjiang vinegar. In terms of physiochemical properties, both red and black date's vinegar were not significantly different (p > 0.05). Use of 50% and 80% methanol with 25 min of ultrasonication for extraction seemed more effective. The total phenols, flavonoids, antioxidant activity, carotenoids, and physiochemical analysis of the red and black date's vinegar indicated that vinegar from dates (red or black dates) is a competitive product in the marketplace. [ABSTRACT FROM AUTHOR]

Copyright of Taiwanese Journal of Agricultural Chemistry & Food Science is the property of Agricultural Chemical Society of Taiwan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study was carried out to determine the phenolic contents and the antioxidant activity of four nuts with different solvent extract. Total phenolic compounds, flavonoids, and proanthocyanidin were quantified. Antioxidant activity was evaluated by various in vitro tests, including ferric reducing power, phosphomolybdenum method assay, and free radical scavenging activity. The results showed that the total phenolic contents varied between 0.30 g GAE/100 g (peanuts) and 1.65 g GAE/100 g (walnuts); the flavonoid contents varied between 0.17 g QE/100 g (peanuts) and 0.41 g QE/100 g (hazelnut). The phenolic contents of four nut extracts exhibit potent antioxidant activity. Indeed, walnuts were the richest in total phenolic content and demonstrated the highest potential for overall antioxidant capacity using ferric reducing power assay (FRP), phosphomolybdenum method assay, and free radical scavenging activity (FRSA). Phenolic amounts positively correlated with antioxidant activity tested. [ABSTRACT FROM AUTHOR]

Cerrado biome represents an area with great biodiversity. Some of its plants have significant ethnopharmacological uses, with specific purposes. Croton urucurana Baill., for instance, was previously acknowledged for its anti-hemorrhagic, anti-inflammatory, antiseptic, healing, and potentially antifungal and entomopathogenic actions. Nevertheless, the compounds supporting these empirical applications are still unknown. Accordingly, this work was designed to achieve a complete characterization of the phenolic profile of different botanical tissues obtained from C. urucurana, and also to verify how different operational conditions (different drying temperatures and extraction conditions) affect that profile. All samples were further characterized by HPLC–DAD–ESI/MSn, and results were compared by advanced chemometric tools. In general, the drying temperatures that maximize the extraction yield of specific individual phenolic compounds were established. Likewise, it was possible to verify that samples extracted with the hydroethanolic solution allowed higher phenolic yields, either in individual compounds (except (epi)catechin-di-O-gallate) or total phenolics. The identification of the best operational conditions and phenolic profiles associated with each C. urucurana botanical part contributes to enabling their use in food or pharmaceutical-related applications.

Abstract One prevailing issue for assessing the performance of hydrothermal liquefaction is understanding the role of the extraction solvent used for product separation. This study evaluated the extraction agent's impact on the hydrothermal liquefaction products and energy efficiency. Three representative solvents (acetone, dichloromethane, and toluene) were chosen with three representative high-carbohydrate, protein, and ash content feedstocks (Chlorella sp., Nannochloropsis sp., and Enteromorpha pr., respectively). Extraction of the oil using dichloromethane led to the highest biocrude oil yield (dry biomass) for Chlorella sp. (48.8%), toluene for Nannochloropsis sp. (23.3%), and acetone for Enteromorpha pr. (9.8%). The solvent selection led to a maximum variation of 20.4% for all oil yields. Dichloromethane produced high energy recovery values (maximum: 67.1%) and low energy consumption ratios (minimum: 0.06) regardless of the feedstock chemical composition. Dichloromethane also led to consistently high net energy values and high fossil energy ratios amongst all feedstocks. We speculate that the solvent polarity, chemical structure, hydrogen bonding, and dipole-dipole interactions influenced output parameters by the selective isolation and extraction of the chemical compounds in the biocrude oil. This study suggested that the extraction solvent selection should be carefully considered and normalized for the reporting of hydrothermal liquefaction yields and energy efficiency values. Highlights • Solvents impact biocrude production/energy efficiency of hydrothermal liquefaction. • Three solvents led to different C/N/S distributions in the hydrothermal products. • Dichloromethane led to the highest biocrude (48.8%) yield of algae. • Dichloromethane led to the highest energy recovery/lowest energy consumption ratio. • Combined effect of polarity/structure/hydrogen bonding/dipole-dipole interactions. [ABSTRACT FROM AUTHOR]

This study show how a few medicinal herbal plant extract can extensively affect on some pathogenic microorganisms for human in exceptional attention and unique solvent. Each of H2O, ethanol and methanol was used for extraction. The plant parts was used individualy to find the most effective part, three species (Isatis tinctoria, Isatis busichaina and Isatis lusitanica) was used in this study to determine the natural products effect on four common pathogenic bacteria Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and Enterococcus faecalis. The extraction was done by using H2O, ethanol and methanol. The results show that most of used plants have vital effect. Extracted each of flower, I. tinctoria was show the best results according to other speciess. Extracted leaf of I. tinctoria by methanol was show the best result on S. aureus and E. faecalis. The Inhibition zone was around 6mm at 75% concentration. The flower was follow the leaf for inhibition zone area and followed by the stem. Depend on the results, the methanol was show highest number, then ethanol and the lowest inhibition zone area was for H2O extraction. [ABSTRACT FROM AUTHOR]

Antioxidant activity (AOA) and phytochemical content of Moringa oleifera Lam leaves were determined as a function of their age and extraction solvent. Fresh Moringa leaves aged 30, 45, and 60 days were harvested and extracted with three solvents; methanol, ethanol, and water. AOA of leaf extracts was measured using radical scavenging assays (DPPH, ABTS, antiperoxide activity [APA]) and reducing assays (FRAP and total antioxidant capacity [TAC]), and these were correlated with total polyphenols (TPC), total flavonoids (TFC), and chlorophyll contents of leaves. Significant variability (p < 0.05) in TPC and AOA of Moringa leaf extracts was observed with age and extraction solvent as well as their interaction. TPC and TFC increased with maturity, except in aqueous extract. The 60‐day‐old leaves showed highest TPC, TFC, and tocopherol contents with highest DPPH activity. On their part, 30‐day‐old leaves recorded better vitamin C, chlorophyll, and carotenoids with highest ABTS activity and APA. Methanol was best extraction solvent for TPC (4.6 g GAE/100 g DM) while ethanol was for flavonoids (1.8 g CE/100 g DM). Ethanol extracts exhibited the highest DPPH activity (53.3%–71.1%), while both ethanolic and methanolic extracts had similar and higher ABTS+ activity (3.83–3.86 g AAE/100 g DM). Strong positive correlations (r ≥ 0.8; p < 0.05) were observed between chlorophyll content and DPPH, ABTS, and APA, suggesting that chlorophyll was the major contributor to AOA. TAC was highest in aqueous solvent. Free radical scavenging activity in Moringa leaves is positively correlated to chlorophyll, TFC, and TPC while reducing power is positively correlated to chlorophyll and TPC. AOA of fresh Moringa leaf extract is a function of its phytochemical content and is influenced by both the age of the leaves and the extraction solvent used. Methanolic and ethanolic extracts of 45‐day‐old Moringa leaves exhibited best antioxidant potentials. Antioxidant activity of fresh Moringa oleifera Lam leaves is a function of its phytochemical content and is influenced by both the age of the leaves and the extraction solvent used. W: water extract; E: ethanol extract; M: methanol extract. 30, 45, and 60 represent the age of leaves in days. TAC: total antioxidant capacity; TP: total polyphenols; TF: total flavonoids; CHL: chlorophyll; Vit C: vitamin C; Caro: carotenoids; Toco: tocopherols; FRAP: ferric reducing/antioxidant power; APA: antiperoxide activity. [ABSTRACT FROM AUTHOR]

Summary: Nine solvents of varying polarity (water, methanol, ethanol, isopropyl alcohol, acetone, n‐butyl alcohol, ethyl acetate, chloroform and petroleum ether) were used to determine the optimal extraction solvent that gives the highest yield of bioactive compounds from six Asparagus Officinalis L root (AR) cultivars from China and New Zealand. The contents of total phenolics (TPC), total flavonoids (TFC), total saponins (TSC) and caffeic acid (CA) were determined. Antioxidant assessments included ferric reducing/antioxidant power (FRAP), 2, 2′‐azinobis‐(3‐ diphenyl‐ethylbenzothiazoline‐6‐sulphonic acid) radical cation (ABTS) and β‐carotene bleaching activity assays. The results indicated that yellow AR from China had the highest content of TPC, TFC, TSC and CA compared to other AR cultivars. The most effective solvents for bioactive compound recoveries and antioxidant activities from A. officinalis L root extraction were ethanol and methanol. The content of CA in ethanol extracts of yellow AR achieved 92.0 mg g−1 DE. [ABSTRACT FROM AUTHOR]

The effects of using solvents with different polarities on the yields of extracting phenolic compounds and antioxidant activity of novel food Alhydwan seed flour were investigated. The extraction solvents used include methanol, ethanol, acetone, diethyl ether, ethyl acetate and hexane. Results showed the efficiencies of the solvents in the extraction of phenolic compounds and antioxidant activities were in this order: methanolic extract < ethanolic extract < acetone extract < diethyl ether extract < ethyl acetate extract < hexane extract. The phenolic content was 63.82-177.08 mg of gallic acid equivalents/g and the yield extract ranged as low as 8.49-126.10%. The results have shown that the properties of extraction solvents significantly affected extraction yield, total phenolic compounds and antioxidant activity of the Alhydwan seed extract. Furthermore, results showed that the methanol extraction resulted in the highest yield (80%), higher phenolic compounds and better antioxidant activity compared to the other solvents. [ABSTRACT FROM AUTHOR]

Methods were optimized for extraction and quantification of anthocyanins (ACY) and vitamin C in potatoes. Acidified aqueous methanol (70%) was the optimal extraction solvent and freeze-drying significantly improved the extraction yield of ACY. The content of ACY varied widely in five potato cultivars from 0.42 to 3.18 mg/g dry weight, with the latter being the highest value found in the Finnish cultivar ‘Synkeä Sakari’. Compared with dithiothreitol (DTT), tris(2-carboxyethyl) phosphine hydrochloride (TCEP) was more efficient in reducing dehydroascorbic acid (DHA) to ascorbic acid (AA) and for quantifying the content of total ascorbic acid (TAA). For raw potatoes, quantification of TAA after treatment with TCEP was more reliable than a direct analysis of AA, whereas AA can be analyzed directly in steam-cooked samples. The TAA contents in the three potato cultivars were around 0.30–0.35 mg/g dry weight. The loss of AA in steam cooking was 24%. [ABSTRACT FROM AUTHOR]

The dielectric properties of a methanol-water mixture were measured at different temperatures from 20 to 80 °C at two frequencies 915 MHz and 2450 MHz. These frequencies are most commonly used on industrial and domestic scales respectively. In this study, the dielectric properties of a methanol-water mixture were found to be dependent on temperature, solvent concentration, and presence of plant matrix. Linear and quadratic equations were developed to establish the dependency between factors. At 2450 MHz, the dielectric constant of methanol-water mixtures was significantly affected by concentration of methanol rather than by temperature, whereas the dielectric loss factor was significantly affected by temperature rather than by methanol concentration. Introduction of potato peel led to an increase in the effect of temperature on the dielectric properties of the methanol fractions. At 915 MHz, both the dielectric properties were significantly affected by the increase in temperature and solvent concentration, while the presence of potato peel had no significant effect on the dielectric properties. Statistical analysis of the dissipation factor at 915 and 2450 MHz revealed that both temperature and solvent concentration had a significant effect on it, whereas introduction of potato peels at 915 MHz reduced the effect of temperature as compared to 2450 MHz. The total phenolic yield of the microwave-assisted extraction process was significantly affected by the solvent concentration, the dissipation factor of the methanol-water mixture and the extraction time.

A antioxidant activities of red sumac fruits (semi ripe) (Rhus coriaria) extracts were evaluated and compared with Butylated Hydroxy Toluene (BHT) as a positive control compared sample by using reducing power test, B-Carotene bleaching test, Hydrogen peroxide scavenging activity test and FTC (Ferric thiocyanate) assay. Red sumac fruits were extracted with different solvents (methanol, ethanol, aceton, diethyl ether, ethyle acetate and hexan). The properties of extraction solvents significantly affected extraction yield ,total phenolic compounds and antioxidant activity of red sumac extract, methanol(80%) gave highest extracted yield from red sumac fruits. Also methanolic extract showed highest content of total phenolic compounds compared with other extraction solvents used in study. The methanolic cude extract of red sumac fruits had better antioxidant activity compared with samples treated with extracts by other extraction solvents. The antioxidant activities could be arranged as follow :BHT Keywords Antioxidant activity --- Red Sumac --- Extraction solvent --- الفعالية المضادة للاكسدة، السماق الاحمر، مذيبات الاستخلاص

Samples from three different mating stages (before, during and after mating) of the Mediterranean fruit fly Ceratitis capitata were used in this experiment. Samples obtained from whole insects were subjected to extraction with the two mixtures of solvents (acetonitrile/water (A) and methanol/acetonitrile/water (B)) and a comparative study of the extractions using the different solvents was performed. Direct immersion-solid phase microextraction (DI-SPME) was employed, followed by gas chromatographic-mass spectrometry analyses (GC/MS) for the collection, separation and identification of compounds. The method was validated by testing its sensitivity, linearity and reproducibility. The main compounds identified in the three different mating stages were ethyl glycolate, α-farnesene, decanoic acid octyl ester, 2,6,10,15-tetramethylheptadecane, 11-tricosene, 9,12-(Z,Z)-octadecadienoic acid, methyl stearate, 9-(Z)-tricosene, 9,11-didehydro-lumisterol acetate; 1,54-dibromotetrapentacontane, 9-(Z)-hexadecenoic acid hexadecyl ester, 9-(E)-octadecenoic acid and 9-(Z)-hexadecenoic acid octadecyl ester. The novel findings indicated that compound compositions were not significantly different before and during mating. However, new chemical compounds were generated after mating, such as 1-iodododecane, 9-(Z)-tricosene and 11,13-dimethyl-12-tetradecen-1-acetate which were extracted with both (A) and (B) and dodecanoic acid, (Z)-oleic acid, octadecanoic acid and hentriacontane which were extracted with (A) and ethyl glycolate, 9-hexadecenoic acid hexadecyl ester, palmitoleic acid and 9-(E)-octadecenoic acid, which were extracted with solvent (B). This study has demonstrated that DI-SPME is useful in quantitative insect metabolomics by determining changes in the metabolic compounds in response to mating periods. DI-SPME chemical extraction technology might offer analysis of metabolites that could potentially enhance our understanding on the evolution of the medfly.

The study aims to develop and validate HPLC and UV-visible spectroscopy methods for the determination of Thymoquinone (TMQ) content in different solvent extracts of N.sativa L. seed. Evaluation of free radical scavenging effect of different solvent extracts of TMQ was investigated. Extraction of solvent was done by adding 20 ml of the following solvent (hexane, methanol, ethanol, ethyl acetate and water) to one gram of blackseed and in a conical flask, respectively. The mixtures were then incubated on a water bath at 40 oC for 2 and 4 hours, respectively. The mixtures were then centrifuged at 4000 rpm for 10 minutes at 4 oC. The extracts were then quantitatively analyzed using HPLC and UV-visible spectrophotometry. The free radical scavenging activity of TMQ extracts was studied using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The results obtained from HPLC indicate that TMQ extracted using hexane at 4 hours (0.075 mg/ml, p < 0.05) was significantly higher compared to other extraction solvents used. The results obtained from UV-vis spectroscopy analysis indicate that the methanol extract at 4 hours (0.00957 mg/ml, p < 0.05) was significantly higher compared to other extraction solvents used. Methanol extracts at 2 hours showed the highest free radical scavenging activity (95.8 %) compared to other extraction solvents. The results obtained show that hexane extracted the most TMQ at 4 hours. Methanol extract demonstrated the highest free radical scavenging activity. [ABSTRACT FROM AUTHOR]

Abstract Dimethyl ether was previously evaluated by the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) and considered to give rise to no safety concerns under the conditions of use and the maximum residual limits proposed by the applicant. The present scientific opinion of the EFSA CEF Panel deals with the re‐evaluation of the safety of dimethyl ether as an extraction solvent under new intended conditions of use and new maximum residual limits. The applicant requests a change in the residual limit of dimethyl ether in defatted animal protein products (in particular collagen) from 0.009 mg/kg to 3 mg/kg, and a new use for the extraction of protein products to yield gelatin with a residual limit of 0.009 mg/kg is also requested. The Panel notes the maximum residual limit requested by the applicant is much higher than the existing limit. Nonetheless, the margin of exposure for this new application is considered to be adequate. No new toxicity data were provided for dimethyl ether and, since the previous EFSA evaluation, only two in vitro genotoxicity studies have become available. These studies do not indicate any genotoxic potential for the assessed substance. The Panel thus considers that the use of dimethyl ether as an extraction solvent, under the intended conditions of use and with the proposed residual limits of 3 mg/kg in the defatted protein products and 9 μg/kg specifically in gelatin, is of no safety concern.

Ascorbic acid or vitamin C is mostly found in natural products such as fruits and vegetables. Ultra performance liquid chromatography (UPLC) method has been developed to compare the ascorbic acid content in some fresh fruits (apple, orange) and vegetables (carrot, beet, cherry tomato) extracts with two different extraction solvents; i) 9% metaphosphoric acid, ii) 3% citric acid. The compound has been detected and quantified by the use of UPLC equipped with Photodiode Array (PDA) detector. The amount of ascorbic acid detected in fruits and vegetables extracts prepared with the two solvents mentioned was different. For the orange extracted using citric acid 3% recorded the highest concentration of ascorbic acid (38.2mg/100g FW) higher than with 9% metaphosphoric acid (33.3mg/100g FW), respectively the extractions of both varieties of apples, carrot, beet and cherry tomato with metaphosphoric extraction solvent recorded the highest values of ascorbic acid: 4.1mg/100g FW in case of ‘Golden’, 9.92mg/100g FW for carrot and 13.56mg/100g FW for beet. The results showed that ascorbic acid content was higher by extraction with 9% metaphosphoric acid as compared, by extraction with 3% citric acid. [ABSTRACT FROM AUTHOR]

The selectivity of a suitable organic solvent is key for extraction in liquid-phase microextraction experiments. Nevertheless, the screening process remains a daunting task. Our research aimed to study the relationship between extraction efficiency and extraction solvents, analytes, and finally select the appropriate extraction solvent. In the present article, β-blockers and six extraction solvents were chosen as the models and hollow-fiber liquid-phase microextraction was conducted. The relationship was built by statistical analysis on the data. Factors affecting extraction efficiency including the logarithms of the octanol/water partition coefficient (log Po/w) of analytes, acid dissociation constants, the logarithms of the octanol/water partition coefficient of solvents and pH of the sample solution were investigated. The results showed that a low water solubility of extraction solvent is the foundation to ensure higher extraction efficiency. Moreover, when Δlog Po/w > 0, a higher extraction efficiency is observed at lower Δlog Po/w, on the contrary, when Δlog Po/w < 0, extraction efficiency is higher as the absolute value of Δlog Po/w becomes greater. Finally, the relationship between enrichment factor and extraction solvents, analytes was established and a helpful guidance was provided for the selection of an optimal solvent to obtain the best extraction efficiency by liquid-phase microextraction. [ABSTRACT FROM AUTHOR]

Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) can begin to tease apart the molecular character of sedimentary organic matter (SOM). We therefore tested five different solvents (aqueous base, CHCl 3 , MeOH, pyridine and water) for their ability to extract a representative fraction from two organic rich lacustrine sediments, Mangrove Lake, Bermuda (MLB) and Mud Lake, Florida (MLF). Following comparison using liquid state nuclear magnetic resonance spectroscopy (NMR) and negative ion mode electrospray ionization mass spectrometry (FTICRMS) we found that pyridine was the optimal solvent, extracting a more diverse (10–100× greater integration for carbonyl, amide and amine groups) and a larger number of peaks on average (1375–1450 vs. 380–1450). Comparison of the pyridine extracts between MLB, MLF and two organic poor sediments from the Mississippi River Delta and Bayou Grande (Pensacola, FL) showed that only 4.9% of the molecular formulae were common to all four and that unique formulae made up the highest proportion of the assignments. The use of pyridine for extracting immature (Holocene) SOM for FTICRMS analysis can therefore be widely applied to immature sediments and produce representative spectra. [ABSTRACT FROM AUTHOR]

In Central Mexico, commercial plantations of pink cedar (Acrocarpus fraxinifoliusWhight & Arn.) from 7 to 15 years old are ready for harvesting to obtain wood products without current bark use. Therefore, the aim of this work was to study ethanolic and hot water extracts fromA. fraxinifoliusbark of 7-year-old (young) and 13-year-old (mature) trees. Yields, total phenolic, flavonoid, and proanthocyanidin contents, as well radical scavenging activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radicals, as well by ferric-reducing antioxidant power (FRAP) and low-density lipoprotein inhibition assays were estimated. Extracts of young tree barks showed higher phenolic content and better scavenging activity than extracts from mature tree barks; ethanolic extracts were superior to the aqueous ones. Positive correlations between polyphenol content and scavenging activity were observed. Results suggest thatA. fraxinifoliusbark loses phenolic content and antiradical activity as it ages. Bioactive phenolics such as gallic acid, catechin, epicatechin, and catechin gallate were identified by HPLC-DAD. [ABSTRACT FROM PUBLISHER]

Dimethyl ether was previously evaluated by the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) and considered to give rise to no safety concerns under the conditions of use and the maximum residual limits proposed by the applicant. The present scientific opinion of the EFSA CEF Panel deals with the re-evaluation of the safety of dimethyl ether as an extraction solvent under new intended conditions of use and new maximum residual limits. The applicant requests a change in the residual limit of dimethyl ether in defatted animal protein products (in particular collagen) from 0.009 mg/kg to 3 mg/kg, and a new use for the extraction of protein products to yield gelatin with a residual limit of 0.009 mg/kg is also requested. The Panel notes the maximum residual limit requested by the applicant is much higher than the existing limit. Nonetheless, the margin of exposure for this new application is considered to be adequate. No new toxicity data were provided for dimethyl ether and, since the previous EFSA evaluation, only two in vitro genotoxicity studies have become available. These studies do not indicate any genotoxic potential for the assessed substance. The Panel thus considers that the use of dimethyl ether as an extraction solvent, under the intended conditions of use and with the proposed residual limits of 3 mg/kg in the defatted protein products and 9 μg/kg specifically in gelatin, is of no safety concern. [ABSTRACT FROM AUTHOR]

A simple dispersive liquid–liquid microextraction (DLLME) method, based on retrieval of the extraction solvent by magnetic particles and followed by HPLC–UV analysis, was proposed for the determination of UV filters in environmental water samples. The new method uses vortex agitation in the DLLME process to achieve rapid equilibrium. Another feature of the proposed method is that the retrieval of the extraction solvent is accomplished by functionalized magnetic particles rather than by special designed vessels or refrigeration and thawing process associated with DLLME when low-density extraction solvent was used. The parameters that may influence the extraction, including vortex time, volume of extraction solvent, weight of the magnetic particles, volume of desorption solvent, pH, and ionic concentration of the sample solution, were investigated in detail. Under the optimized conditions, the limits of detection for the target UV filters were in range of 0.7–12.3 ng mL−1. The results also demonstrated good linearity and precision, with the regression coefficients above 0.9989 and the RSDs below 4.4%, respectively. [ABSTRACT FROM PUBLISHER]

Ascorbic acid or vitamin C is mostly found in natural products such as fruits and vegetables. High performance liquid chromatography (HPLC) method has been developed and validated to compare the ascorbic acid content in Benincasa hispida (Bh) fruit extract with three different extraction solvents; i) 3% metaphosphoric acid, ii) 3% citric acid and iii) distilled water. The compound has been detected and quantified by the use of HPLC coupled with UV-Vis detector. The amount of ascorbic acid detected in Bh fruit extract prepared with different extraction solvents; 3% metaphosphoric acid, 3% citric acid and distilled water were 13.18, 7.91 and 9.42 mg/100g respectively. Total run time was 6 min and the retention time was 2.60 min. Calibration curve was linear with the concentration range 1.00 -- 16.00 µg/ml. Limits of detection was 0.24 µg/ml, limit of quantification was 0.81 µg/ml and recovery was 93.52%. The result showed ascorbic acid content is higher in Bh fruit extract with 3% metaphosphoric acid, followed by extract with distilled water and 3% citric acid. Thus, Bh is another novel fruit/ vegetable potentially used as food ingredient as it contains a good source of ascorbic acid that can be good for one's health. [ABSTRACT FROM AUTHOR]

Two wheat varieties grown in Upper and Delta Egypt were compared for their total phenolic content and antioxidant activities. Three solvent systems have been used to prepare the antioxidant extracts from whole wheat and its bran fraction. The three solvent systems included 50% acetone ( v / v ), 70% methanol ( v / v ) and 70% ethanol ( v / v ). Antioxidant activities were tested using DPPH radical scavenging activity and total flavonoid content. The results showed that the extraction solvents and wheat varieties significantly altered the total phenolics and antioxidant activity of whole wheat and bran, and 50% acetone is a recommended solvent for extracting phenolic compounds from the tested wheat and bran. Also data indicated that the bran fraction was rich in total phenolic content and high power for radical scavenging activity than whole wheat. These results showed that wheat bran could be considered as a potential source of antioxidant agent. Therefore, durum wheat variety (Beni-suef-3) showed high level of total phenol contact and antioxidant properties in bran fraction than common wheat variety (Gemiza-9). So, whole meal wheat products maximize health benefits and strongly recommended for use in food processing. [ABSTRACT FROM AUTHOR]

Sclerotium rolfsiiSacc. is an important fungal pathogen affecting the production of tomato (Lycopersicon esculentumMill.). Conventional control methods using chemicals are expensive, which constitute environmental hazards. This has necessitated the search for alternatives in botanicals. Ethanol and supernatant solution of fermented maize slurry extracts fromOcimum gratissimum, Cymbopogon citratus, Xylopia aethiopica, Aframomum meleguetaandAllium sativumwere evaluated.In vitrotest was carried out at 1, 2, 3, 4 and 5% concentrations against the pathogen. Mycelial growth was significantly reduced in the following descending order:O. gratissimum > A. melegueta > A. sativum > X. aethiopica > C. citratus. Supernatant solution extracts ofO. gratissimumandA. meleguetaat 5% concentration gave highest mycelial reduction (0.00 mm), respectively, whileO. gratissimumethanol extract recorded highest mycelial reduction (0.23 mm) among the ethanol extracts. Supernatant solution of fermented maize slurry extracts ofO. gratissimumandA. meleguetaat 5% concentration was more effective in reducing mycelial growth ofS. rolfsii. [ABSTRACT FROM AUTHOR]

The complete extraction of analytes is of utmost importance when analyzing matrix samples for mycotoxins. Mycotoxins consist of substances with widely different physicochemical properties; therefore, the loss of toxins that occurs in multi-mycotoxin methods due to compromises in the extraction solvent is currently a topic under discussion. With regard to fumonisins, several extractants from recently published multi-mycotoxin methods were investigated when analyzing unprocessed and processed maize matrices. All extractants were tested in a validated on-site method and the extraction yields were compared to those of an HPLC-FLD reference method (EN 14352). Most of the compared multi-mycotoxin methods that have been published were only for analyzing fumonisins in maize or maize-meal; we have applied the extractants of these methods to processed, complex maize matrices for the first time. Our results show that, for extractions with aqueous acetonitrile mixtures with the addition of acid, e.g. MeCN/HO/acetic acid (79/20/1, v/v/v), higher extraction yields are obtained than with MeCN/HO (80/20, v/v), in both spiked and naturally contaminated maize matrices. But compared to the results of the reference method EN 14352, the two extractants did not show a similar extraction efficiency. Overall, the extractant MeCN/MeOH/HO (1/1/2, v/v/v) turned out to be the most appropriate extractant applied in all experiments, obtaining the best and most comparable extraction yields and recoveries. Furthermore, our investigations showed that, with some of the tested extraction solvents, e.g. MeCN/HO (75/25) containing 50 mmol/l formic acid, stark differences occur when analyzing spiked and naturally contaminated matrices. With spiked matrices, recoveries of approximately 80-110 % were obtained, but with naturally contaminated matrices no results comparable to the EN method have been achieved. In contrast, a double extraction with MeCN/HO/formic acid (80/19,9/0,1, v/v/v), followed by a second polar extraction step with MeCN/HO/formic acid (20/79,9/0,1, v/v/v), led, for most naturally contaminated samples, to comparable results with the EN method. However, for spiked samples, the same extractant led to raised recoveries of between 120 and 140 %. For some processed matrices, like taco-chips, all tested extractants showed a poor extraction efficiency for fumonisins. By extending the extraction time from 1 to 15 min, a result comparable to that of the reference method could also be obtained for the extractant using MeCN/MeOH/HO (1/1/2, v/v/v). As this extractant has been used in our recently published method (Trebstein et al. Mycotoxin Res 25:201, ), this work also presents an update on this method with respect to the extended extraction time. [ABSTRACT FROM AUTHOR]

The common and routine procedure for the quantification of chlorophyll a (chl a) in aquatic studies has a series of steps. Here, we sought to find optimal conditions for phytoplankton cell harvesting, chl a extraction, and chl a measurement and calculation, to find an effective, cost-saving, safe, and environment-friendly procedure for determining phytoplankton chl a concentration. We replaced the traditional GF/C filters with inorganic polymer flocculants (IPFs) and clay for phytoplankton harvesting, and then various solvents (acetone, ethanol, DMF, and DMSO), IPFs (PAC, PFS, and PAFS) and clay were tested for their suitability for chl a extraction, with or without homogenization at different temperatures for different extraction durations. About 0.3-1.0 g l of PAC or PFSA combined with 1.0-2.5 g l clay were found to provide optimal conditions in terms of yield and cost for phytoplankton cell harvesting from water samples. Based on our results, we recommend flocculation and centrifugation instead of glass-fiber membrane filtration for harvesting phytoplankton cells from environmental water samples, 95% ethanol for chl a extraction without homogenization and heating, and spectrophotometry to determine chl a concentration. [ABSTRACT FROM AUTHOR]

An experimental study was conducted to investigate the extraction of oxidized sulfur compounds from gas oil. Solvents used for this purpose included acetone, acetonitrile, methanol and propanol. The effect of solvent concentration, solvent to gas oil ratio, temperature, time and number of stages was studied. To select the best solvent and conditions for extraction, two criteria were considered: high desulfurization and more hydrocarbon recovery. Results showed that extraction time and temperature have no significant effect. Methanol for low ability of extraction of oxidized sulfur compounds and propanol for low hydrocarbon recovery were excluded from further experiments. After the tests, the optimum conditions for extraction were determined to be 85% acetone, solvent/feed ratio of 1, two stages extraction in ambient temperature and enough time for mixing. In this condition 85% of sulfur compounds of gas oil containing 1,670 ppmw S were separated and 95% of gas oil was recovered. [ABSTRACT FROM AUTHOR]