scholarly journals Comparison of different extraction solvents for assay of the polyphenol content in the peel and pulp of 21 apple cultivars from Macedonia

2016 ◽  
Vol 35 (1) ◽  
pp. 29 ◽  
Author(s):  
Ana Petkovska ◽  
Viktor Gjamovski ◽  
Marina Stefova
Keyword(s):  
Extraction Efficiency ◽  
Spectrophotometric Methods ◽  
Acetone Water ◽  
Freeze Dried ◽  
Apple Peel ◽  
Total Anthocyanins ◽  
Apple Cultivars ◽  
Extraction Solvents ◽  
The Republic

Apples (Malus domestica Borkh.) contain a large array of phenolic compounds belonging to flavonoids and non-flavonoids. This study systematically evaluates the polyphenolic content of 21 apple cultivars from the Republic of Macedonia, both commercial and autochthonous, applying spectrophotometric methods for the determination of total polyphenolic compounds, total flavonoids, total anthocyanins and total flavan-3-ols. The reliability of these methods was checked by confirming the method linearity and accuracy with standards and spiked samples. The efficiency of acetone, water, methanol and a mixture of methanol/water (90 : 10, V/V) as extraction solvents was compared. Evident differences between extracts obtained from freeze-dried apple peel and pulp, extracted with different solvents, and analyzed with the four spectrophotometric tests, were observed and discussed. The most satisfactory extraction efficiency was achieved using methanol/water (90 : 10, V/V) mixture. The results obtained from the methanol/water extracts illustrate evident differences between polyphenol contents and reveal the diversity in polyphenols, total flavonoid and flavanol composition between the assayed commercial and autochthonous cultivars. The maximum abundance of polyphenols was noticed in the peel of Tetovka and Livadarka cultivars (15.63 mg/g GAE and 14.85 mg/g GAE, respectively) and in the pulp of Pasalma, Tetovka and Livadarka cultivars (12.55 mg/g GAE, 11.45 mg/g GAE and 11.22 mg/g GAE, respectively).

scholarly journals Determination of the polyphenol contents in Macedonian grapes and wines by standardized spectrophotometric methods

2010 ◽  
Vol 75 (1) ◽  
pp. 45-59 ◽  
Author(s):  
Violeta Ivanova ◽  
Marina Stefova ◽  
Fabio Chinnici
Keyword(s):  
Extraction Efficiency ◽  
Total Phenolics ◽  
Principal Component ◽  
White Wine ◽  
Total Flavonoids ◽  
Spectrophotometric Methods ◽  
Acetone Water ◽  
Total Anthocyanins ◽  
Grape Varieties

Wines and grapes contain a large array of phenolic compounds belonging to non-flavonoids and flavonoids. This study evaluates the polyphenolic contents of six commercial red and white Macedonian wines and four grape varieties. Spectrophotometric methods were applied for the determination of the total phenolics, the total flavonoids, the total anthocyanins and the total catechins. The efficiency of acetone/water (80/20) and methanol/water (80/20) solutions for the extraction of polyphenols from grape pulp, seeds and skins were compared. The best extraction efficiency was achieved using acetone/ water. The obtained results showed that Macedonian grapes are rich in polyphenols, whereby the highest concentration of total phenolics was found for Vranec grapes. The analyzed wines contained high contents of polyphenol; the highest contents were found for Disan wine produced from the Vranec variety of grapes (1515 mg/L total phenolics, 1103 mg/L total flavonoids, 237 mg/L total anthocyanins and 845 mg/L total catechins). Principal component analysis was employed to check possible groupings of the studied red and white wine samples. A clear separation of white wines from red ones was observed.

Comparison of hydrophilic and hydrophobic deep eutectic solvents for pretreatment determination of sulfonamides from aqueous environments

2019 ◽  
Vol 11 (46) ◽  
pp. 5901-5909 ◽  
Author(s):  
Yuxin Ma ◽  
Qi Wang ◽  
Tao Zhu
Keyword(s):  
Water Samples ◽  
Extraction Efficiency ◽  
Deep Eutectic Solvents ◽  
Environmental Water ◽  
Phase System ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
Aqueous Environments ◽  
Extraction Solvents

Two types of deep eutectic solvents were synthesized for an aqueous two-phase system to determine the sulfonamides from environmental water samples. The ChCl-Ph based ATPS showed good extraction efficiency. The method avoids use of a large number of extraction solvents.

scholarly journals Extraction Efficiency of Different Solvents and LC-UV Determination of Biogenic Amines in Tea Leaves and Infusions

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
U. Gianfranco Spizzirri ◽  
Nevio Picci ◽  
Donatella Restuccia
Keyword(s):  
Quantitative Determination ◽  
Biogenic Amines ◽  
Extraction Efficiency ◽  
Dansyl Chloride ◽  
Tea Leaves ◽  
Tea Infusions ◽  
Extraction Solvents

Biogenic amines (BAs), that is, spermine, spermidine, putrescine, histamine, tyramine,β-phenylethylamine, cadaverine, and serotonin, have been determined in several samples of tea leaves, tea infusions, and tea drinks by LC-UV method after derivatization with dansyl chloride. Different extraction solvents have been tested and TCA 5% showed better analytical performances in terms of linearity, recovery percentages, LOD, LOQ, and repeatability than HCl 0.1 M and HClO40.1 M and was finally exploited for the quantitative determination of BAs in all samples. In tea leaves total BAs concentration ranged from 2.23 μg g−1to 11.24 μg g−1and PUT (1.05–2.25 μg g−1) and SPD (1.01–1.95 μg g−1) were always present, while SER (nd–1.56 μg g−1), HIS (nd–2.44 μg g−1), and SPM (nd–1.64 μg g−1) were detected more rarely. CAD and PHE were determined in few samples at much lower concentrations while none of the samples contained TYR. Tea infusions showed the same trend with total BAs concentrations never exceeding 80.7 μg L−1. Black teas showed higher amounts of BAs than green teas and organic and decaffeinated samples always contained much lower BAs levels than their conventional counterparts.

Improving Extraction of Fumonisin Mycotoxins from Brazilian Corn-Based Infant Foods

2003 ◽  
Vol 66 (5) ◽  
pp. 854-859 ◽  
Author(s):  
VIKASH SEWRAM ◽  
GORDON S. SHEPHARD ◽  
WALTER F. O. MARASAS ◽  
MARIA FERNANDA PENTEADO M. de CASTRO
Keyword(s):  
Extraction Efficiency ◽  
Corn Starch ◽  
Aqueous Methanol ◽  
Infant Foods ◽  
Matrix Interferences ◽  
Corn Products ◽  
Extraction Solvents ◽  
Comparison Of The Results ◽  
The City

The current AOAC International methods for the determination of fumonisins have been validated for corn and cornflakes but have produced low recoveries and high variability when applied to processed corn products for infants. Hence, an investigation was undertaken to improve the extraction efficiency for fumonisins by investigating the use of different extraction solvents. Corn-based infant foods containing cornmeal, corn starch, and corn flour were purchased in the city of Campinas, state of Sao Paulo, Brazil, and were analyzed for fumonisins B1 (FB1), B2 (FB2), and B3 (FB3) following extraction with a range of solvents. Comparison of the results from each of the samples indicated that acidified 70% aqueous methanol at pH 4.0 provided the best overall performance, whereas a methanol/boric acid (pH 9.2) mixture displayed poor extraction efficiency. Extraction with acidified 70% aqueous methanol showed seven of eight test samples to be positive for FB1 (range, 30 to 6,127 μg/kg; relative SD, 4.2 to 51.7%), two of eight samples to be positive for FB2 (range, 53 to 1,738 μg/kg; relative SD, 4.5 to 5.3%), and one of eight samples to be positive for FB3 (575 μg/kg). For samples in which extraction with phosphate-buffered mixtures (pH 3) proved superior, the method suffered from poor chromatography due to interfering compounds. The findings indicate that matrix interferences play a significant role in the extractability, cleanup, and chromatography of the fumonisins.

Influence of Various Solvent-Water Mixtures on the Extraction of Dieldrin and Methomyl Residues from Radishes

1982 ◽  
Vol 65 (5) ◽  
pp. 1112-1117
Author(s):  
Willis B Wheeler ◽  
Neal P Thompson ◽  
Robert L Edelstein ◽  
Ramon C Littell ◽  
Richard T Krause
Keyword(s):  
Water Content ◽  
Extraction Efficiency ◽  
Carbon 14 ◽  
Solvent Water ◽  
Optimum Water Content ◽  
Acetone Water ◽  
Extraction Solvents ◽  
Root Tissues ◽  
Optimum Water ◽  
Water Ratio

Abstract The effect of organic solvent/water ratios on the extraction of field-incurred residues of dieldrin and methomyl from radishes was determined. 14CDieldrin and 14C-methomyl were applied separately to radishes in commercial formulations at rates of 0.2 and 0.9 kg/ha, respectively. Fourteen days post-application, the radishes were harvested and fresh root tissues were extracted using a Polytron homogenizer. Acetone, acetonitrile, and methanol containing 0,10, 20, 30, 40, and 50% water were used as extraction solvents. For methomyl residues, the optimum water content of acetonitrile-water extraction mixtures was 40-50%; less than 40% water reduced the ability of acetonitrile to extract carbon- 14. Methanol and acetone were nearly as efficient as 50% acetonitrile-water and were apparently not influenced by solvent/water ratios. For dieldrin, low water content slightly reduced the extraction efficiency of acetonitrile, with the optimum water content also being 40-50%. Percentage of water appeared to have little overall effect on methanol extraction efficiency. The extraction efficiency of acetone was lower than that of the other 2 solvents, and this effect was independent of the acetone/water ratio. Approximately 20% of the 14C-dieldrin residue was bound to radish roots 14 days post-application.

Method for the Determination of Aflatoxin M1 in Fluid Milk and Milk Products

1973 ◽  
Vol 56 (6) ◽  
pp. 1431-1436 ◽  
Author(s):  
Walter A Pons ◽  
Alva F Cucullu ◽  
Louise S Lee
Keyword(s):  
Neutral Lipids ◽  
Milk Powder ◽  
Aflatoxin M1 ◽  
Reliable Determination ◽  
Milk Products ◽  
Average Recovery ◽  
Acetone Water ◽  
Freeze Dried ◽  
Fluid Milk

Abstract The method described utilizes acetone-water (77+23) for extraction of M1 from milk and milk products in a 3 min blender extraction. Phospholipids and soluble proteins in the primary extract are removed by treatment with lead acetate, and residual neutral lipids in the treated extract are removed by partition into hexane. Aflatoxin M1 is partitioned into chloroform, which is then washed with salt solution, and the chloroform is evaporated. The residue is dissolved in chloroform, and M1 is resolved on silica gel-coated plates developed in chloroform-acetone-2-propanol (850+100+50). This basic procedure is applicable to fluid milk and reconstituted freeze-dried milk powder at levels as low as 0.1 μg M1/L. Extracts of nonfat dry milk, evaporated and condensed milk, and cheeses, which require further cleanup before TLC, are purified on a cellulose-aqueous methanol partition column to allow reliable determination of M1 at levels as low as 0.2 Mg/L or kg. Average recovery of M1 added to fluid milk at levels of 0.1–1.0 μg/L was 106% without the use of the cleanup column and 90% when the column was used to purify the extracts. Average recovery of M1 added to other milk products at a level of 0.2 Mg/L or kg was 88%. The precision of the method (coefficient of variation) was estimated to be ±16% at 0.2 Mg/L in fluid milk, and ±4% at a 34 Mg/kg level in contaminated freeze-dried milk.

Determination of catechin and epicatechin in the peel of apple varieties resistant and non-resistant to apple scab

2010 ◽  
Vol 64 (6) ◽  
Author(s):  
Marek Gołębiowski ◽  
Edmund Maliński ◽  
Małgorzata Szankin ◽  
Mariusz Marszeniuk ◽  
Monika Paszkiewicz ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Solid Phase Extraction ◽  
Mass Spectra ◽  
Solid Phase ◽  
Apple Scab ◽  
Phase Extraction ◽  
Apple Trees ◽  
Apple Peel ◽  
Apple Cultivars

AbstractCatechin and epicatechin were analysed in the peel of six apple cultivars (three resistant and three non-resistant to apple scab). Two methods of analytical sample preparation following extraction were tested: solid phase extraction and column separation with Sephadex LH-20 coupled to a differential refractometric detector. Prior to GC and GC-MS analyses, these compounds were silylized. This permitted co-injection with standards and the comparison of retention values and mass spectra with those recorded for standards. The content of catechin and epicatechin in apple peel is discussed in relation to the resistance of apple trees to scab.

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

Reduction of Potassium in Kidney Proximal Tubules to Aid in Electron Probe X-Ray Microanalysis of Calcium

1985 ◽  
Vol 43 ◽  
pp. 474-475
Author(s):  
A. LeFurgey ◽  
P. Ingram ◽  
L.J. Mandel
Keyword(s):  
Smooth Muscle ◽  
Proximal Tubule ◽  
Electron Probe ◽  
Clinical Applications ◽  
Proximal Tubules ◽  
Rabbit Kidney ◽  
Target Cells ◽  
X Ray ◽  
Freeze Dried

For quantitative determination of subcellular Ca distribution by electron probe x-ray microanalysis, decreasing (and/or eliminating) the K content of the cell maximizes the ability to accurately separate the overlapping K Kß and Ca Kα peaks in the x-ray spectra. For example, rubidium has been effectively substituted for potassium in smooth muscle cells, thus giving an improvement in calcium measurements. Ouabain, a cardiac glycoside widely used in experimental and clinical applications, inhibits Na-K ATPase at the cell membrane and thus alters the cytoplasmic ion (Na,K) content of target cells. In epithelial cells primarily involved in active transport, such as the proximal tubule of the rabbit kidney, ouabain rapidly (t1/2= 2 mins) causes a decrease2 in intracellular K, but does not change intracellular total or free Ca for up to 30 mins. In the present study we have taken advantage of this effect of ouabain to determine the mitochondrial and cytoplasmic Ca content in freeze-dried cryosections of kidney proximal tubule by electron probe x-ray microanalysis.

Colorimetric Determination of Amoxicillin in Pure and some Pharmaceutical Formulations Via Reaction with Potassium Permanganate as Oxidant Reagent

2019 ◽  
Vol 10 (02) ◽  
Author(s):  
Abbas Shebeeb Al-kadumi ◽  
Sahar Rihan Fadhel ◽  
Mohammed Abdullah Ahmed ◽  
Luma Amer Musa
Keyword(s):  
Potassium Permanganate ◽  
Pharmaceutical Preparations ◽  
Pharmaceutical Formulations ◽  
Atomic Emission ◽  
Basic Medium ◽  
Photometric Method ◽  
Colorimetric Determination ◽  
Spectrophotometric Methods ◽  
Label Claim

We proposed two simple, rapid, and convenient spectrophotometric methods are described for the determination of Amoxicillin in bulk and its pharmaceutical preparations. They are based on the measurement of the flame atomic emission of potassium ion (in first method) and colorimetric determination of the green colored solution for manganite ion at 610 nm formed after reaction of Amoxicillin with potassium permanganate as oxidant agent (in the second method) in basic medium. The working conditions of the methods were investigated and optimized. Beer's law plot showed a good correlation in the concentration range of 5-45 μg/ml. The detection limits and relative standared deviations were (2.573, 2.814 μg/ml) (2.137, 2.498) for the flame emission photometric method and (1.844, 2.016 μg/ml) (1.645,1.932) for colorimetric methods for capsules and suspensions respectively. The methods were successfully applied to the determination of Amoxicillin in capsules and suspensions, and the obtained results were in good agreement with the label claim. No interference was observed from the commonly encountered additives and expectancies.

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