Dimethylformamide Extraction Research Articles

Extraction, purification, and quantification of hesperidin from the immature Citrus grandis/maxima fruit Nepal cultivar

Abstract. Manikyam HK, Tripathi P, Patil SB, Lamichhane J, Chaitanya MVNL, Patil AR. 2022. Extraction, purification, and quantification of hesperidin from the immature Citrus grandis/maxima fruit Nepal cultivar. Asian J Nat Prod Biochem 20: 21-26. Hesperidin, a flavanone group of flavonoids and a 7-O-rutinoside of hesperitin is abundantly present in citrus fruits. Pomelo or Citrus grandis (L.) Osbeck/ C. maxima (Burm.) Merr. is grown and cultivated in Nepal as seasonal edible fruit. Pomelo has flavanone and other chemical constituents. Flavanones like naringin, hesperidin, neohesperidin, and naringenin are present in the fruits of C. grandis. Many extraction techniques have been reported in the extraction and purification of hesperidin citrus fruits like sweet lemons, grapefruits, mandarins, etc. However, little information has been provided on hesperidin content in Pomelo fruits. In order to estimate the quantity of hesperidin in the Pomelo fruits of Nepal, we have first time made study. The immature Pomelo fruits of size 2-7 cm were collected from the cultivation field and dried completely. The pulverized fruit powder with moisture content less than 15% was subjected to 5% methanolic acetic extraction and Dimethylformamide (DMF) solvent extraction in Soxhlet apparatus by refluxing at 90°C in 1:15 ration in three subsequent extractions of each 1 hour. The concentrates were crystalized at freezing temperatures in methanol and further purified by repeating the crystallization process. The white amorphous powder was subjected to RP-HPLC analysis method, chromatographic conditions 285 nm wavelength, C18 column 4.6 mm x 15 cm x 5 µm, flow rate 1.2 mL/minute with injection volume 10 µL run time of 30 minutes, column temperature 40°C. Hesperidin yields were 0.12 g/100 g with acetic acid methanol with a purity of 87% and 0.17 g/100 g in DMF extraction with a purity of 90% with recoveries of 87% in acetic acid methanol extraction and 90% in DMF extraction when compared with standard 93%. Further extraction does not yield any hesperidin content indicating a total of 0.15-0.17 g/100 g of hesperidin content in the whole immature fruit of C. grandis/maxima. Thus we found DMF and 5% methanolic acetic solvents as preferable solvents to extract hesperidin.

Oxidative desulfurization of dibenzothiophene and diesel by hydrogen peroxide: Catalysis of H3PMo12O40 immobilized on the ionic liquid modified SiO2

Here we reported an oxidative desulfurization system for oxidation of sulfur-containing compounds in model oil and diesel by catalysis using SiO2-supported phosphomolybdate hybrid material with 30% H2O2 aqueous solution as the oxidant. Firstly, The SiO2 was modified with 1-propyl-3-triethoxysilyl 3-methylimidazolium chlorid by grafting method. We used the 29Si MAS NMR to demonstrate that the organic silane group was attached to the SiO2 surface by one or two SiOSi bonds. Secondly, the phosphomolybdate was immobilized onto the modified SiO2 to prepare the hybrid material catalyst. The FT-IR, UV–vis, and TG characterization results indicate that the Keggin structure of the [PMo12O40]3− and imidazole ring were remained. The catalyst was used to oxidative desulfurization of dibenzothiophene by H2O2 as the oxidant. Maximum oxidation activity was observed at a loading of 30 wt.% H3PMo12O40 which can complete oxidation 0.2 wt.% of dibenzothiophene at 50 °C and an O/S molar ratio of 3.0 in 30 min. The catalyst could be easily separated by centrifugation and reused for seven times without any deactivation. The high performance of this oxidative desulfurization system was verified in the sulfur removal from a real diesel oil by oxidation followed by dimethylformamide extraction.

Distribution of Vanadium Compounds in Petroleum Vacuum Residuum and Their Transformations in Hydrodemetallization

The distribution of vanadium (V) compounds in the petroleum vacuum residuum (VR) and their transformations in hydrodemetallization (HDM) were investigated. V compounds in the VR and its hydrotreated products were extracted by different solvents in sequence to obtain methanol, dimethylformamide (DMF), and toluene extract fractions. The extracts were further separated into several subfractions using silica gel chromatography with various polar solvents. Positive-ion electrospray ionization (ESI) Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) analyses was used to characterize V compounds before and after HDM. The contents of V compounds in the methanol, DMF, and toluene extracts were 9.04, 22.19, and 62.58%, respectively. The V compounds in the methanol extract were mainly porphyrin with a molecular formula of CnHmN4V1O1, which were found undergoing side-chain cracking and could be removed through hydrotreating. CnHmN5V1O2 species were found in the DMF extracts, which can be easily converted or removed under severe reaction conditions. The V compounds in the toluene extracts were most resistant for hydrotreating, which were speculated as vanadyl porphyrins with complex substituent groups attached to the core porphyrin structures. The results indicated that a highly active HDM catalyst should possess a highly active hydrogenesis property and macropore size distribution for the different V compounds removed.

Catalytic performance of P-modified MoO3/SiO2 in oxidative desulfurization by cumene hydroperoxide

Phosphorous-modified MoO3/SiO2 catalysts with various P/Mo molar ratios (MoPxO/SiO2, x=0.3−3.0) were prepared by co-impregnation and compared with MoO3/SiO2 in the oxidation of dibenzothiophene by cumene hydroperoxide. The addition of P significantly enhanced the catalytic performance, and MoP1.0O/SiO2 exhibited the highest oxidation activity. XRD characterization indicated that the active phase of MoP1.0O/SiO2 was amorphous, whereas 31P-NMR measurements revealed that MoP1.0O/SiO2 had a similar connectivity of Mo-O-P to H3PMo12O40. The total sulfur of a hydrotreated diesel was reduced from 298 to 5ppmw by oxidation with CHP and subsequent dimethylformamide extraction.

Optimization of flavanones extraction by modulating differential solvent densities and centrifuge temperatures

Understanding the factors influencing flavonone extraction is critical for the knowledge in sample preparation. The present study was focused on the extraction parameters such as solvent, heat, centrifugal speed, centrifuge temperature, sample to solvent ratio, extraction cycles, sonication time, microwave time and their interactions on sample preparation. Flavanones were analyzed in a high performance liquid chromatography (HPLC) and later identified by liquid chromatography and mass spectrometry (LC–MS). The five flavanones were eluted by a binary mobile phase with 0.03% phosphoric acid and acetonitrile in 20min and detected at 280nm, and later identified by mass spectral analysis. Dimethylsulfoxide (DMSO) and dimethyl formamide (DMF) had optimum extraction levels of narirutin, naringin, neohesperidin, didymin and poncirin compared to methanol (MeOH), ethanol (EtOH) and acetonitrile (ACN). Centrifuge temperature had a significant effect on flavanone distribution in the extracts. The DMSO and DMF extracts had homogeneous distribution of flavanones compared to MeOH, EtOH and ACN after centrifugation. Furthermore, ACN showed clear phase separation due to differential densities in the extracts after centrifugation. The number of extraction cycles significantly increased the flavanone levels during extraction. Modulating the sample to solvent ratio increased naringin quantity in the extracts. Current research provides critical information on the role of centrifuge temperature, extraction solvent and their interactions on flavanone distribution in extracts.

Oxidative desulfurization of dibenzothiophene and diesel over [Bmim] 3PMo 12O 40

A hybrid material ([Bmim] 3PMo 12O 40) was synthesized by reacting H 3PMo 12O 40 with the ionic liquid 1-butyl-3-methyl imidazolium bromide. SiO 2-supported [Bmim] 3PMo 12O 40 showed a high catalytic activity in the oxidation of dibenzothiophene (DBT) with 29% H 2O 2 aqueous solution as the oxidant. Maximum activity was observed at a loading of 20 wt.% [Bmim] 3PMo 12O 40 on SiO 2, and 100% DBT conversion was achieved at 60 °C, atmospheric pressure, and an oxygen to sulfur (O/S) molar ratio of 3.0 in 100 min. The high performance of [Bmim] 3PMo 12O 40/SiO 2 might be attributable to its amphiphilicity, which enhances adsorption of both H 2O 2 and sulfur-containing compounds. [Bmim] 3PMo 12O 40/SiO 2 could be easily separated by centrifugation and reused without deactivation after seven runs. Quinoline and carbazole had slightly positive effects on DBT oxidation, whereas indole had a negative effect. The high performance of [Bmim] 3PMo 12O 40 was verified in the sulfur removal from a real diesel by means of oxidation followed by dimethylformamide extraction.

Chlorophyll extraction methods for the quantification of green microalgae colonizing building facades

Abstract The occurrence of microalgae on man-made surfaces such as roof tiles, concrete, building facades and other artificial surfaces in urban areas, where it causes aesthetically unacceptable discolouration of the surfaces, represents a conspicuous problem because of its contribution to biodeterioration and accelerated weathering. So far, microbial colonization has been recorded mainly macroscopically, and hence semi-quantitatively evaluated by the degree of discolouration, and the visual data assigned to a colour scale for algal infestation intensity. However, these assessments lack inter-calibration and suffer from colour modifications because of co-occurring fungi or background properties. By using chlorophyll a as a specific biomarker of aeroterrestrial microalgae, an extraction method was therefore developed to quantify biomass. Two green microalgae, Stichococcus sp. and Chlorella sp., were isolated from facades of buildings, established as monocultures and used in the present study. Algal samples are best preserved by freezing in liquid nitrogen followed by lyophilisation and subsequent storage at −18 °C. Dimethyl formamide (DMF) proved to be the best extraction solvent. Mechanical homogenisation improved extraction by up to 20%. However, chlorophyll a extraction efficiency was strongly species-specific and further influenced by the growth conditions, i.e. whether cells were in logarithmic or stationary growth phase. To achieve maximum values for chlorophyll a from samples of unknown algal species composition and physiological state it was found necessary to make at least two 24-h extractions in DMF. If the second extraction step contributed > 20 % to the total chlorophyll a concentration, a third DMF extraction was applied. Using this biomarker assay, up to 313 mg chlorophyll a m−2 was obtained from building facades, equivalent to c. 100 g algal fresh weight, which represents a high organic load.

The analysis of PAHs nitrogen derivatives in the sewage sludges of upper Silesia, Poland

The dimethylformamide extracts from sewage sludges from a chosen sewage — treatment plant in highly industrialized region of Poland were investigated. Using the column chromatography with Al2O3 and silicic acid as the stationary phases, the fraction of azaarenes has been separated. GC-MS analysis of azaarenes fraction made it possible to identify 10 azaarenes and several of their alkyl derivatives, which dominate in the organic matter extracted from sewage sludges. The silicic acid column chromatography in connection with the reduction of nitroarenes and derivatization with pentafluoropropionic acid anhydride yielded an enriched nitrofraction. Nitroarenes present in this fraction as amide derivatives were also analysed by GGMS method. There was found presence of 3 nitroarenes and their methyl derivatives.

Metal-organic associations in two extracts from nine soils amended with three sewage sludges

An aerobic sewage sludge, and two anaerobic sewage sludges, one of which was pretreated with chlorine, were separately incubated with nine northeastern US soils to evaluate sludge-metal complexation reactions with soil organic matter. Soil organic matter was separately extracted with sodium pyrophosphate and dimethylformamide (DMF). The extracts were fractionated on non-polar, non-ionic macroreticular and ion exchange resins into acidic, neutral, and basic hydrophilic solute fractions and acidic, neutral, and basic hydrophobic solute fractions. There were distinct differences in metal complexes present in the extracts between the two extractants, especially for Cr and Cd. Also, the total amount of metals recovered from the sludges varied, usually in the order: aerobic > anaerobic > pretreated anaerobic sludge. In the pyrophosphate extracts, hydrophilic neutrals (carbohydrates) were associated with Ni and Pb, and hydrophilic bases (amino acids) were associated with Pb, and hydrophobic bases (porphyrins) were associated with Cu, Ni, and Pb. Zinc was associated with all fractions, but none predominated. However, in the DMF extracts, hydrophilic acids (uronic acids) were associated with Cr, hydrophilic bases (amino acids) with Ni, Cr, and Pb, hydrophobic acids (phenols) with Pb and Zn, and hydrophobic bases (prophyrins) were associated with Cd. Only very few metals were associated with hydrophobic neutrals (hydrocarbons). The kinds of Ni-organic fractions present in the DMF extracts from most of the soils were more closely related to plant uptake by vegetables in a previous study—with the Ni-amino acid fraction being absorbed by plants more easily then the Ni-porphyrin fraction. Differences between the extractants and among the soils can be ascribed to the inherent properties of these two variables.

Coal characterization by on-line pyrolysis-field ionization mass spectrometry

Pyrolysis-field ionization mass spectrometry (Py-FIMS) was used for the first time to directly characterize Chinese coals and their extracts. The summed mass spectra (about 30 magnetic scans) of four coal samples and the dimethylformamide extracts of two very different coals were registered between 50° and 750°C using linear heating in high vacuum (10−3 Pa) and approximately 6 min temperature rise time. Utilizing temperature-programmed pyrolysis and FI as soft ionization mode, the spectra displayed almost exclusively molecular ions of the evolved products. The thermograms, i.e. the intensities of the total ion current and selected ions were plotted versus the scan number, heating time and temperature. In general, two maxima in these thermograms were observed, which were different for the coals and reflected their carbon/hydrogen content. Comparing the mass spectra of the low temperature part (first maximum) with summed spectra of the extracts shows an interesting similarity. In contrast, the high temperature part (second maximum) indicates the products of thermo-degradation. The applied method is a fast and convenient tool for the characterization of evolved volatiles and thermal degradation products of coals and coal extracts.

Graft polymerization of acrylonitrile onto wheat straw

Acrylonitrile was graft polymerized onto ground, water-washed wheat straw using Fe2+-H2O2 as initiator. Reaction conditions were selected to minimize homopolymer formation and maximize the amount of polyacrylonitrile (PAN) grafted to straw. Polymerizations typically yielded straw-g-PAN containing 30–35% PAN. A two-step fractionation scheme was developed for determining the relative amounts of PAN grafted to cellulose, hemicellulose, and lignin. This scheme involved (1) delignification of straw-g-PAN with sodium chlorite followed by removal of lignin-grafted PAN by extraction with dimethylformamide (DMF), and (2) hydrolysis of the hemicellulose component with 1 N trifluoroacetic acid followed by DMF extraction of hemicellulose-grafted PAN. Product remaining after these two treatments was assumed to be cellulose-g-PAN. When relative amounts of PAN grafted to cellulose, hemicellulose, and lignin were compared with relative percentages of these components present in wheat straw, the percentage of total PAN grafted to lignin was less than its relative percentage in straw, whereas that grafted to hemicellulose was considerably more. Although the use of Ce4+ as initiator gave little or no polymer with whole, water-washed straw, grafted polymerization occurred when delignified straw was used as substrate. Relative amounts of PAN grafted to cellulose and hemicellulose were not greatly different from those observed with Fe2+-H2O2 initiation onto whole straw.

Hydrogenation of coal-derived liquids in the presence of rhodium complexes

Hydrogenation of 473–573 K distillate derived from the product of catalytic hydrogenation of coal in the presence of hydrogen-donor solvent and ethyl alcohol and dimethyl-formamide extracts of the tar from low-temperature (fluidized-bed) coal carbonization have been investigated in the presence of rhodium complexes. The complexes used (293–393 K; 0.1–5 MPa) bpth in homogeneous and in immobilized forms are catalytically active in hydrogenation of those coal-derived liquids. However, the increase of H/C atomic ratio is low. The catalysts in the immobilized form have not been deactivated in several catalytic cycles following.

Gliadin proteins in the developing wheat seed

AbstractIn extracts of developing seeds of wheat (Triticum aestivum L., cultivars Scout 66, Cheyenne, Nugaines and INIA 66R) examined by polyacrylamide gel electrophoresis, gliadin proteins appeared at 12‐15 days post‐anthesis with mobilities covering nearly the whole range found with mature seeds. Some differences among extractants [2M dimethylformamide (DMF); 2M urea; 60% ethanol; the aluminium lactate‐lactic acid electrophoresis buffer, pH 3.2] in both intensity and occurrence of specific bands were observed. With immature seeds, 60% ethanol extracts produced a maximum number of bands and least background colour, but DMF and urea extracts showed bands from 12‐ to 15‐day seeds at least as well as 60% ethanol extracts despite more background colour. Aluminium lactate buffer extracts occasionally yielded bands not found with other extractants, but gave poor extraction from immature seeds and relatively heavy background staining with mature seeds, especially in the w‐gliadin (lowest mobility) region. A quantitative sodium dodecyl sulphate‐electrophoresis procedure1 was used to follow the formation of proteins in various molecular weight ranges (cv. Scout 66 only). At 12‐18 days post‐anthesis, synthesis of protein of molecular weight 30 000‐37 000 accelerated, consistent with the onset and acceleration of formation of α‐, β‐, and some y‐gliadins. Protein in a band of 44 000 molecular weight formed in similar fashion. In other molecular weight ranges, gliadin bands could not be positively identified because of the complexity of the banding pattern of the total protein.

Automated Procedure for the Estimation of Total Polyphenol Content in Beer, Wort, Malt, and Barley

An automated procedure using 4-aminoantipyrine as a chromogen was used to estimate total polyphenol content in beer, wort, malt, and barley. For 23 beers with a wide range in test results, the correlation between the manual European Brewery Convention method and the automated method was 0.88. Barley and malt determinations were made on 30% aqueous dimethylformamide extracts of grain. Cultivar differences were found, suggesting the use of the procedure to select for polyphenol content in lines from barley breeding programs.

The xanthate method of grafting. IV. Grafting of acrylonitrile onto high-yield pulp

A series of pulps with different lignin content was prepared from a softwood sodium bisulfite high-yield pulp. Sodium chlorite at pH 4 served as the delignification agent. The resulting pulps were subjected to grafting with acrylonitrile using the cellulose xanthate–hydrogen peroxide redox system to initiate the copolymerization reaction. The resulting products were isolated and analyzed for homopolymer content by dimethylformamide extraction. The results indicate that the presence of larger amounts of lignin in pulp may have a favorable effect on grafting. The plots of total conversion as well as of polymer loading show a minimum centered around approximately 15% of lignin. This minimum is observed invariably at five different reaction times and it coincides with the maximum concentration of reductive groups in the pulps as well as with the maximum cation exchange capacity. The parameter of grafting efficiency has a tendency to increase with rising lignin content, reflecting the lower relative yields of homopolymer obtained with high-lignin pulps. This observation is discussed in relation to possible chain transfer reactions by lignin.

Sensitive and quantitative nitroblue-tetrazolium test for detecting chronic granulomatous disease.

New method for nitroblue-tetrazolium (NBT) test was developed by the following modifications. (1) After 10 N KOH treatment, bathochromic shift in the maximal absorption took place from 515 nm to 710 nm and the optical density of the new peak was 5 times higher than that of non-treated sample. In this assay, dimethylformamide extraction was substituted for pyridine. (2) Because of the smallness of the incubation mixture (100 μl), the background of the test was greatly reduced. (3) Increase in the concentration of latex particles elevated the NBT reducing activity. In consideration with the background absorption, 2.9-5.7×108 particles/assay was set as the optimal condition. The particles themselves, however, did not interrupt the reading of optical density in this system. In this modified method, 3 ml of blood was enough to estimate the NBT reducing activity in the duplicate tests (6 samples). This assay system is, therefore, applicable for weak children, from whom the collection of the large volume of the blood is not desirable.

Determination of residual solvent in oilseed meals and flours: I. Dimethyl formamide extraction procedure

AbstractA procedure is described for determination of residual acetone and hexane in cottonseed and soybean meals and flours by extraction of the residual solvent with dimethyl formamide (DMF)‐water (95∶5) followed by gas liquid chromatography analysis of the DMF extracts. A representative group of samples was analyzed both by this procedure and one employing iso‐octane as extractant. In all cases where residual solvent was found, the amount was markedly greater when aqueous DMF was the extracting solvent.