Wyniki wyszukiwania - Biblioteka Nauki

1

Development and validation of a TLC-densitometric method for the simultaneous quantitation of icariin and L-arginine from commercial formulations

100%

Gupta P. K. , Kuber V. V. , Ghosh V. K. , Bhope S. G. , Sharma V. , Purohit S.

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2011

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tom Vol. 23, no. 3

447--458

EN

A simple, rapid, and specific thin layer chromatographic (TLC) method has been developed and validated for the simultaneous estimation of icariin and L-arginine from commercial polyherbal formulations for sexual dysfunction. The separation of the methanol extract of these formulations was achieved on silica gel 60 F254 aluminum backed TLC plates by using ethyl acetate-acetone-glacial acetic acid-formic acid-water 12:2:1:2:2 (υ/υ) as mobile phase. Densitometric analysis of icariin and L-arginine was monitored in absorbance mode at 270 and 195 nm, respectively. The linear regression analysis data for the calibration plots for icariin and L-arginine showed good linear relationship with r2 = 0.9984 +- 0.01 and 0.9968 +- 0.02, in the concentration ranges of 250–750 and 500–1500 ng/spot, respectively. The method was validated for precision, robustness, and recovery. The average percentage recovery was found to be 98.26% for icariin and 99.63% for L-arginine. The limits of detection and quantitation were 72, 116 and 238, 383 ng/spot, respectively, for icariin and L-arginine. Statistical analysis proves that the method is repeatable and selective for the estimation of the targeted drugs. Since the proposed mobile phase effectively resolves the icariin and L-arginine, this method can be applied for the identification and quantitation of these components in herbal extracts and marketed formulations.

2

Determination of the fatty acids in fish tissue and feed — comparison of different methods and statistical evaluation

100%

Trbović D. , Polak T. , Demšar L. , Parunović N. , Dimitrijević M. , Nikolić D. , Đorđević V.

Acta Chromatographica

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2018

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tom Vol. 30, no. 3

175--179

EN

With the aim to reinforce laboratory competence in the field of testing the quality of fish from aquaculture, a study on the precision of fatty acid (FA) analyses in fish meat and fish feed was undertaken. Different methods were performed in laboratories. In situ transesterification method and extraction of lipids from the fish were followed by capillary gas chromatography with flame ionization detection. The reproducibility (R) values of the majority of FAs were less than 3% of their absolute values. Differences in calculating ionization detector response factors and/or autoxidation caused by faulty sample-handling could lead to variation in quantification of FAs in fish, especially for FA C22:6n-3. Statistical analysis showed a significant correlation between the two laboratories' quantifications of FAs in fish and fish feed (Pearson's correlation coefficient; r = 0.987, r = 0.994, and r = 0.997; for fish Z [trout], fish Š [rainbow trout], and fish feed, respectively). Overall, adequate accuracy was obtained in this study. The proposed method provides a fast and efficient means of identifying fish and feed for quality control purposes.

3

Voltammetric quantitation at the mercury electrode of the anticholinergic drug flavoxate hydrochloride in bulk and in a pharmaceutical formulation

86%

Ghoneim M. M. , El-Attar M. A. , Razeq S. A.

Open Chemistry

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2007

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tom 5

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nr 2

496-507

EN

Flavoxate hydrochloride, 2-piperidinoethyl 3-methyl-4-oxo-2-phenyl-4-H-chromene-8-carboxylate, is a smooth muscle antispasmodic. Its electrochemical behavior was studied at the mercury electrode in buffered solutions containing 30% (v/v) methanol using dc-polarography, differential-pulse polarography, cyclic voltammetry, and linear sweep-and square-wave adsorptive stripping voltammetry. Sensitive and precise procedures were developed for determination of bulk flavoxate hydrochloride and in the pharmaceutical formulation Genurin® S.F, without sample pretreatment or extraction. Limits of quantitation (LOQ) of 1 × 10−5, 5 × 10−6, 1 × 10−8 and 1 × 10−9 M flavoxate hydrochloride were achieved by dc-polarography, differential-pulse polarography, linear sweep and square-wave adsorptive stripping voltammetric, respectively. [...]

4

HPLC analysis in drug level monitoring of K027

86%

Nurulain S. M. , Kalász H. , Szegi P. , Kuca K. , Adem A. , Hasan M. Y. B. , Hashemi F. , Tekes K.

Acta Chromatographica

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2013

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tom Vol. 25, no. 4

703--710

EN

HPLC monitoring of pharmacokinetics was done in two body compartments of rats following intramuscular treatments with three different doses of K027, a bispyridinium mono-aldoxime type of antidotes to organoposphate intoxicated subjects. Reversed-phase HPLC separation with electrochemical detections was done to monitor the onset, the maximum level, and offset in K027 concentration. Serum level of K027 showed a fast onset, independently from the doses of K027. Drug level in brain was showing an essentially delayed kinetics.

5

Quantitation of poly(diallyldimethylammonium chloride) by complexation with acid orange 7 dye

72%

Ziółkowska D. , Szeflińska I. , Shyichuk A.

Polimery

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2014

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tom T. 59, nr 11-12

859--861

EN

The anionic dye Acid Orange 7 (AO7) was applied for quantitative determination of poly(diallyldimethylammonium chloride) (PDDA) in aqueous solutions. The PDDA polymer forms colloidal complexes with the AO7 dye resulting in spectral changes. Increase in the polymer concentration up to 0.10 mmol(mer)/dm3 leads to decrease in absorbance at wavelengths in the range between 450 and 500 nm. The obtained calibration dependences between absorbance and concentration fulfill linear equation with quite small variance (s2 = 1.56 · 10-2). The proposed method of PDDA quantitation requires weak acidic medium (pH » 3.5-6.5) and low values of ionic strength (I » 20 mM).

PL

Zdolność barwnika — oranżu kwasowego II (AO7) do tworzenia koloidalnych kompleksów z poli(chlorkiem dimetylodialliloamonowym) (PDDA) została wykorzystana do ilościowej analizy tego polimeru w roztworach wodnych. Wykazano, że oznaczenie stężenia PDDA za pomocą pomiaru absorbancji z wykorzystaniem krzywej wzorcowej jest możliwe w zakresie długości fali od 450 do 500 nm. Wzrostowi stężenia polimeru do 0,10 mmol(mer)/dm3 towarzyszy spadek intensywności głównego piku w widmie barwnika AO7, przy czym krzywa kalibracyjna ma charakter prostoliniowy. Zaproponowana metoda oznaczania PDDA wymaga zastosowania środowiska słabo kwasowego (pH » 3,5—6,5) i o małych wartościach siły jonowej (I » 20 mM).

6

Optimization of extraction of pyrrolizidine alkaloids from plant material

72%

Mroczek T. , Widelski J. , Głowniak K.

Chemia Analityczna

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2006

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tom Vol. 51, No. 4

567-580

EN

Various techniques of extraction of pyrrol izidine alkaloids (PAs) from comfrey have been developed and compared. Different extraction media: methanol, ethanol, 1% methanolic solution of tartaric acid, 2.5% HC1 solution, 5% CH.COOH solution, alkaline chloro form- -methanol mixture at various temperatures (room temperature, 50-60°C, solvent's boiling point) have been used in various extraction techniques (percolation, electric basket, ultrasonic water bath) and various extraction times. Total concentration of pyrrolizidine alkaloids (PAs) was estimated from UV-VIS spectrophotometric studies according to Dann- -Mattocks procedure. For the most promising extraction techniques one determined recoveries of monocrotaline added to crude pre-extracts. Extraction and co-extraction processes were investigated using UV-VIS spectra of the adducts of 3,4-dehydro-PAs and Ehrlich's reagent. The best result of PAs extraction from comfrey was obtained using 1% methanolic solution of tartaric acid and electric basket technique at the temperature 100 š 5°C for 2 h. Possible applications of the method have been discussed.

PL

W prezentowanej pracy podjęto badania optymalizacji ekstrakcji alkaloidów pirolizydy-nowych (PAs) z materiału roślinnego (źywokostu lekarskiego). Zastosowane metody obejmowały ekstrakcję metanolem, etanolem, l % roztworem kwasu winowego w metanolu, 2.5% roztworem kwasu solnego, 5% roztworem kwasu octowego, alkaliczną fazą organiczną (chloroform-metanol). Badano również wpływ temperatury ekstrakcji (pokojowa, 50-60°C, wrzący rozpuszczalnik) wykorzystując różne techniki ekstrakcyjne (perkolacja, ekstrakcja w płaszczach grzewczych, ekstrakcja wspomagana ultradźwiękami) oraz wpływ czasu ekstrakcji na odzysk PAs z surowca roślinnego. Caikowitą zawartość PAs oznaczono w oparciu o spektrofotometrię UV-VIS wg metody Danna i Mattocksa. W przypadku najbardziej obiecujących metod ekstrakcji oznaczono odzysk wzorca monokrotaliny dodawanego do pre-ekstraktu tuż przed rozpoczęciem właściwej ekstrakcji. Analizując widma U V—VIS adduktów 3,4-dehydro-PAs z odczynnikiem Ehrlicha możliwa była analiza stopnia ekstrakcji PAs z surowcajak i współekstrakcji substancji balastowych. Najlepszą wydajnością oraz najmniejszym stopniem współekstrakcji balastów charakteryzowała się 2-godzinna ekstrakcja wrzącym (temp. 100 š 5°C) 1% roztworem kwasu winowego w metanolu w płaszczach grzewczych. Przedyskutowano także potencjalne wykorzystanie opracowanej metody.

7

The results of compression forces applied to the isolated human calvaria

72%

Tubbs R. S. , Murphy R. L. , Golden J. B. , Etheridge B. , Wellons J. C. , Blount J. P. , Salter E. G. , Oakes W. J.

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nr 4

321-325

EN

Data for the force necessary to fracture the isolated calvaria (skull cap) are not available in the extant literature. Twenty dry adult calvaria were tested to failure quasistatically at the vertex using a 15-kN load cell. The forces necessary to fracture or cause diastasis of calvarial sutures were then documented and gross examination of the specimens made. Failure forces had a mean measurement of 2772 N. Initial fractures did not cross suture lines. Prior to complete destruction of the calvaria there were 7 specimens in which all sutures of the calvaria became diastatic, 6 specimens in which the calvaria became diastatic along only the coronal sutures, 2 specimens in which the calvaria became diastatic along only the sagittal suture and 5 specimens in which there were diagonal linear parietal bone fractures. Our hopes are that these data may contribute to the structural design of more safer protective devices for use in our society, assist in predicting injury and aid in the construction of treatment paradigms.

8

Rapid high performance thin layer chromatographic method for quantitation of catechin from extracts of cashew leaves - a short report

72%

Jaiswal Y. , Tatke P. , Gabhe S. , Vaidya A.

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tom 63

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nr 1

EN

Cashew is a tropical tree with immense commercial value and the use of its various parts in the confectionary, food, herbal and tanning industry has gained tremendous importance. Thus, the development of quality control method for routine analysis of various products of this widely used plant would be a great help to analysts. The phytochemistry of this plant has not been explored in detail. Anacardium occidentale Linn. (cashew) is reported to contain many antioxidant and polyphenolic compounds. However, there have been no reports published for the HPTLC analysis of the extracts of cashew leaves. Hence, an attempt has been made to develop a HPTLC method for estimation of catechin from leaf extracts. The present paper reveals a rapid high performance thin layer chromatographic method developed for quantitation of catechin from extracts of cashew leaves. The chromatographic parameters such as solvent system, development time, saturation time, detection wavelength were optimized. The mobile phase toluene: ethyl acetate: methanol: formic acid (6:6:1:0.1v/v/v/v) gave the best resolution for various components. The separation of various components and quantitation of amount of catechin was successfully carried out from extracts of cashew leaves. The aqueous extract of leaves contained a higher amount of catechin as compared to ethanol extract. The presence of tannins and phenolics was visualised as bluish-black bands with 5% alcoholic FeCl3 as visualising agent. The method can prove to be a rapid, sensitive and economic alternative as compared to other chromatographic methods especially HPLC for detection of catechin in various food products and herbal formulations.

9

Quantitation of polyhexamethylene biguanide by photometric titration with Naphthol Blue Black dye

72%

Ziółkowska D. , Syrotynska I. , Shyichuk A.

Polimery

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2014

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tom T. 59, nr 2

160--164

EN

A convenient and reliable method for quantitative determination of polyhexamethylene biguanide in aqueous solutions has been developed, based on complexation of the polymer with Naphthol Blue Black dye. Spectrophotometric titration measuring absorbance at 600 nm leads to characteristic zigzag curves, with the inflexion point at dye to polymer mers molar ratio 1:2. The photometric titration endpoints are characterized with good repeatability, resulting in low variance values. As a result, the limit of polyhexamethylene biguanide determination has been found to be equal to 50 and 150 µmol/dm3 of mers for direct and reverse titration, respectively.

PL

Opracowano nieskomplikowaną, dokładną metodę ilościowego oznaczania biguanidu poliheksametylenowego w roztworach wodnych opartą na reakcji kompleksowania polimeru z barwnikiem Czerń Amidowa 10B. Zmiany widma UV-Vis sugerują, że przy pewnym stosunku molowym stężeń polimeru (w przeliczeniu na mer) i barwnika tworzą się słabo rozpuszczalne kompleksy. Wynikiem miareczkowania spektrofotometrycznego przy długości fali 600 nm są zygzakowate zależności absorbancji od ilości analitu z punktem przegięcia przy stosunku molowym barwnik:polimer wynoszącym 1:2. Zastosowana metoda wyznaczania punktu końcowego miareczkowania charakteryzuje się dobrą powtarzalnością. Zakres oznaczania merów biguanidu poliheksametylenowego wynosi 50 i 150 µmol/dm3, odpowiednio, dla miareczkowania prostego i odwrotnego.

10

Use of solid phase extraction and thin-layer chromatography in screening procedure for quantitation of ethanolamine and its methylated forms in rat liver cells

58%

Bazylak G.

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tom 03

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nr 3-4