Wyniki wyszukiwania - Biblioteka Nauki

1

Comparison of the chromatographic behavior of azines, diazines and their deratives on stationary phases with bonded NH2, CN and diol groups by TLC

100%

Baranowska I. , Świerczek S.

|

1998

|

tom z. 137

89-94

EN

Twelve heterocyclic bases and their deratives have been analysed by TLC on stationary phases with bonded cyano, amino and diol groups with n-propanol/ n-hexanemixtures as mobile phase. The relationship between the RM values of the compounds examined and the composition of the mobile phase has been determined as the function RM=f(logx). The affinity of the individual solutes to the mobile phase and to the stationary phases has been study.

PL

Przeprowadzono analizę chromatograficzną 12 zasad heterocyklicznych metodą TLC stosując jako fazę stacjonarną nośniki ze związanymi grupami amonowymi, diolowymi oraz cyjanowymi w układzie n-propanol/n-heksan. Wyznaczono zależności pomiędzy parametrami retencji RM badanych związków a składem fazy ruchomej korzystając z równania RM = f(logx). Określono wpływ fazy ruchomej, rodzaju nośnika oraz budowy badanych związków na mechanizm retencji.

2

TLC-densitometric analysis of α-escin in bulk drug substance and in pharmaceutical dosage forms

100%

Dolowy M. , Pyka-Pajak A. , Filip K. , Zagrodzka J.

Current Issues in Pharmacy and Medical Sciences

|

2015

|

tom 28

|

nr 3

186-191

EN

A quite simple and rapid TLC-densitometric method for the identification of α-escin (Aescin) in bulk drug substances was developed. In so doing, different chromatographic conditions, including various mobile and stationary phases, were tested. A TLC densitometric determination of the examined compound was performed without using visualizing reagent, yet with the use of appropriate dipping reagents, in order to obtain reliable UV-densitometric measurements of α-escin - a substance which has weak chromophore groups. Herein, the application of a mobile phase containing n-butanolacetic acid-water in volume composition 30:7:13, the use of silica gel 60F254 plates with concentrating zone, and subsequent application of 10% sulphuric acid in ethanol or 5% vanillin in methanol/sulphuric acid, respectively, provided the best results in a TLCdensitometric study of α-escin. The described method was successfully employed to identify α-escin in commercial samples that were in an oral dosage form (tablets) and also in the form of gel containing 20 mg of α-escin.

3

TLC screening in searching for active components in Rhodiola rosea L. roots

100%

Nikolaichuk H. , Choma I. M.

Annales Universitatis Mariae Curie-Skłodowska, sectio AA – Chemia

|

2019

|

tom 74

|

nr 1

EN

Thin layer chromatography (TLC) has been used for screening analysis of extracts from Rhodiola rosea roots. TLC is a fast, simple and inexpensive screening technique, often used in qualitative analysis of plant substances. The results of TLC analysis confirmed presence of sugars, terpenes, terpenoids, saponines and propylpropanoids in Rhodiola roots. The extracts of Rhodiola rosea revealed strong antioxidant activity.

4

Simple and convenient protocol for staining of organic azides on TLC plates by ninhydrin. A new application of an old reagent

89%

Cegielska B. , Kacprzak K. M.

|

2009

|

tom Vol. 54, No. 4

807-812

EN

Operationally simple, general and sensitive method for the visualization of organic azides on TLC plates was developed. The protocol is based on triphenylphosphine-mediated reduction of azides to the corresponding amines which give contrasting color spots with ninhydrin.

PL

Opisano prostą, ogólną i czulą metodę wybawiania azydków organicznych na płytkach TLC, bazującą na ich redukcji do odpowiednich amin, które w reakcji z ninhydryną dają kontrastowo zabarwione plamy.

5

Biennial review of planar chromatography: 2011–2013

88%

Sherma J.

Open Chemistry

|

2014

|

tom 12

|

nr 4

427-452

EN

The most important advances in planar chromatography published between November 1, 2011 and November 1, 2013 are reviewed in this paper. Included are an introduction to the current status of the field; student experiments, books, and reviews; theory and fundamental studies; apparatus and techniques for sample preparation and TLC separations (sample application and plate development with the mobile phase); detection and identification of separated zones (chemical and biological detection, TLC/mass spectrometry, and TLC coupled with other spectrometric methods); techniques and instruments for quantitative analysis; preparative layer chromatography; and thin layer radiochromatography. Numerous applications to a great number of compound types and sample matrices are presented in all sections of the review.

6

A new TLC densitometric method for stability assessment of modafinil

88%

Faisal M. S. , Naz Z. , Shakeel F. , Ahmed S. , Kohli K. , Khar R. K.

|

2009

|

tom Vol. 54, No. 1

77-88

EN

TLC densitometric method for simple and sensitive stability assessment of modafinil has -been developed. The objective was to provide a rapid, precise, robust, and reproducible technique for the analysis of modafinil. The method was validated for bulk drug and tablet , formulations. It could be used to separate the drug from its degradation products. The pro- cedure employed TLC aluminum plates precoated with 60F-254 silica gel as the stationary phase. The solvent system consisted of toluene-chloroform-methanol (1:1:0.5, v/v/v) 'o'o mixture. It provided well-resolved compact spots for modafinil (Rr value 0.46 š 0.01) and allowed for separation of the excipients and degradation products. Densitometric scanning interegation was performed at the wavelength of 220 nm. Calibration plot was linear , (r2 = 0.999) in the analyte concentration range 100-5000 ng per spot. The method was validated with respect to linearity, accuracy recovery, precision, ruggedness, and specificity. The limit of detection and quantification were 20.54 ng per spot and 62.26 ng per spot, respectively. The determined drug content was within the š5% range of the labeled content. The drug was analyzed under different stress conditions in order to study its degradation in the presence of acid, base, and peroxide.

PL

Opracowano densytometryczną metodę TLC pozwalającą na proste i czułe badanie stabilności modafinilu. Opracowana technika była szybka, precyzyjna, odporna na warunki zewnętrzne i powtarzalna. Metodę zwalidowano dla substancji farmaceutycznej i tabletek. Można ją stosować do oddzielenia leku od produktów rozkładu. Jako fazę stacjonarną użyto żel krzemionkowy 60F-254 naniesiony na płytki aluminiowe. Fazę ruchomą stanowiła '"' mieszanina: toluen-chlorofbrm-metanol (1:1:0,5; v/v/v). Otrzymywano dobrze rozdzielone, zwarte plamki modafinilu (wartość Rf 0.46 š 0.01), oddzielone od substancji pomocniczych i produktów rozkładu. Skanowanie densytometryczne prowadzono przy długości fali 220 nm. Krzywa kalibracyjna miała charakter liniowy (r2 = 0,999) w zakresie stężeń analitu 100-5000 ng na plamkę. Metodę zwalidowano w zakresie liniowości, dokładności, odzysku, precyzji, odporności na czynniki zewnętrzne i specyficzności. Granica wykrywalności i oznaczalności ilościowej wynosiły odpowiednio 20,54 ng i 62.26 ng na plamkę. Oznaczana zawartość leku mieściła się w granicach š 5% ilości deklarowanej. Lek analizowano w różnych warunkach stresowych w celu zbadania jego degradacji w obecności kwasów, zasad i nadtlenków.

7

The kernel density estimate as a measure of the performance of one and two-dimensional TLC systems with large retention datasets in the context of their use in fingerprinting

88%

Komsta Ł. , Szewczyk K.

|

2009

|

tom Vol. 21, no. 1

13-27

EN

A new objective chromatographic response function, R K , based on the kernel density estimate, is introduced for estimation of the fingerprinting performance of a particular TLC system (uniformity of retention) for which a large set of experimental R F values of possible components of the mixture is available. The R K criterion is insensitive to large numbers (hundreds or thousands) of R F values, when the previously proposed criteria cease. It can be applied to one and two-dimensional TLC and is easily computed. As an example of its application, the performance of twelve general screening systems was evaluated in the context of herbal extract fingerprinting (88 phytochemical standards) by both one and two-dimensional TLC.

8

Evaluation of thin-layer chromatography systems for analysis of amino acids in complex mixtures

88%

Vasta J. D. , Cicchi M. , Sherma J. , Fried B.

|

2009

|

tom Vol. 21, no. 1

29-38

EN

Different thin-layer chromatography (TLC) systems were evaluated for analysis of 21 biologically important essential and nonessential amino acids in complex mixtures such as biological tissues and fluids. Amino acids were visualized on the layers by derivatization with ninhydrin reagent, and R F values were determined by slit-scanning densitometry. The five systems found to be most useful for analysis of amino acids were cellulose and silica gel high-performance TLC (HPTLC) plates developed with either 2-butanol-pyridine-glacial acetic acid-deionized water, 39:34:10:26, or 2-butanol-pyridine-25% ammonia-deionized water, 39:34:10:26, and ion exchange TLC plates developed with citrate buffer, pH 3.3. Using these five systems with ninhydrin detection, identification of all amino acids except for leucine and isoleucine in complex mixtures is possible, and quantification can be achieved if the amino acid to be quantified is well separated from adjacent components of the mixture. Example chromatograms are illustrated for separation and identification of amino acids in a snail tissue sample on a cellulose HPTLC plate.

9

New N-aryloxy-phthalimide derivatives. Synthesis, physico-chemical properties, and QSPR studies

88%

Tudose M. , Badea F. , Caproiu M. , Beteringhe A. , Maganu M. , Ionita P. , Constantinescu T. , Balaban A.

Open Chemistry

|

2010

|

tom 8

|

nr 4

789-796

EN

Starting from N-hydroxyphthalimide 1 and the reactive fluoro- or chloro-nitroaryl derivatives 2, 3 and 4a-e (2-chloro-3,5-dinitropyridine; 3, NBD-chloride; 4a, 1-fluoro-2,4-dinitrobenzene; 4b, picryl chloride; 4c, 4-chloro-3,5-dinitrobenzotrifluoride; 4d, 2-chloro-3,5- dinitrobenzotrifluoride; 4e, 4-chloro-3,5-dinitrobenzoic acid) the corresponding N-(2-nitroaryloxy)-phthalimide derivatives 5a-e, or 6 and 7 were obtained and characterized by IR, UV-Vis 1H-NMR and 13C-NMR spectroscopy. The TLC behavior and the hydrophobicity of these derivatives have been experimentally evaluated by RM0 parameters (using RP-TLC). The experimental RM0 parameters were compared with the calculated partition coefficient, log P. A QSPR study was also performed to establish possible correlations between the structure and physical properties (λmax and RM0) of compounds 5a-e, 6, and 7. [...]

10

Chemical characterization by TLC, UV, IR, HPLC-MS/MS and NMR of gossypetin-3’-O-glucoside from Talipariti elatum (Sw.) Malvaceae

75%

González J. , Cuéllar A. , Gaysinski M. , Massi L. , Monan M. , Nossin E. , François-Haugrin F.

World News of Natural Sciences

|

2019

|

tom 24

100-116

EN

Talipariti elatum (Sw.) Malvaceae, also known as Blue Mahoe or Mountain Mahoe, commonly named as Majagua azul or Majagua, with red or crimson flowers, is a medicinal tree traditionally used against cough, asthma, catarrh, and expectorant. Its flowers contain a lot different chemical compounds, mainly flavonoids. From red petals of the flowers a flavonol glucoside was isolated and characterized by TLC, UV, IR, HPLC-MS/MS and NMR spectroscopy. Structure analyses of that chemical component revealed that It have the identical glucoside moiety attached to a flavonol skeleton like gossypitrin (gossypetin-7-O--glucoside) but in different position for which the structure of gossypetin-3’-O-glucoside was deduced from HSQC, HMBC, COSY and NOESY correlations.

11

Analysis of Organophosphorus Compounds. 1. Application of Iodine-Azide Reaction for Detection of Thiophosphoorganic Compounds in Thin-Layer Chromatography

63%

Kotyński A. , Kudzin Z. H. , Ciesielski W. , Andrzej Kotyński - Department o f Bioinorganic Chemistry M. U. o. f. Ł. , Zbigniew H. Kudzin - Institute of Chemistry U. o. Ł. , Witold Ciesielski - Institute of Chemistry U. o. Ł.

|

tom 13

PL

Wydrukowano z dostarczonych Wydawnictwu UŁ gotowych materiałów

12

Zastosowanie metody chromatografii cienkowarstwowej do oznaczania pigmentów nieorganicznych

63%

Wróbel E.

Ochrona Zabytków

|

1981

|

nr 3-4

188-196

EN

It was in 1978 that a scientific and research laboratory of the State Enterprise for Monuments Conservation in Warsaw used — for the first time — thin layer chromatography to identify inorganic pigments. Basing on comprehensive literature on the analysis of inorganic ions by means of thin layer chromatography (TLC) nearly 50 methods of the determination of simple ions and their combinations were studied, partially restricting the task to methods of distribution on the most popular carriers. 15 cations entering into the composition of 28 pigments and 1 2 anions entering into the composition of 20 pigments were identidfied. To give all results of the examinations set up in more than 2 0 big tables would exceed the framework of this article. Therefore some details of the examined methods of distribution have been quoted and briefly discussed as representative. When working out methods of the distribution of individual ions or their groups standard pigments and — for comparison purposes — standard salts available in the laboratory were used. Both pigments and standard salts were prepared for spreading on plates by means of proper solvents. Most frequently it was a diluted or concentrated acid and only occasionally a flux or a diluted base. Pigment solutions were prepared and their concentration did not exceed a few per cent (usually 1 per cent solution was employed). Solutions of the examined pigments or corresponding standard salts were spread on plates covered with a layer of a carrier. As a rule Merck’s plates with silicone gel (Kieselgel 60 F22) and a carrier layer (0.25 mm thick) cut from the plates of 20 X 20 cm down to 4 X 9 cm or Merck’s plates with a cellulose carrier (Cellulose F) of 0 .1 mm in thickness and also cut down to 4 x 9 cm were used. Before spreading standards, plates with cellulose were activated in a dryer at 105° С for 10 minÿ plates with silicone gel were activated at 110° С for 1 hour. Standards were spread on plates by means of capillaries, the diameter of which was 0.5 mm. The plates were numbered and then developed in small chromatographic cells (5x3x11 cm) saturated with vapours of the developing system. After developing a chromatogram, the plates were dried in a dryer and developed by spraying with special reagents. Developed chromatograms were photographesd with a Polaroid camera. The obtained results of the studies make it possible to introduce the analysis of pigments by means of thin layer chromatography as a method supplementary to other traditional methods of determination, particularly when only a small quantity of the sample is available and it is composed of several pigments and their determination by traditional methods is impossible.

13

Wybrane techniki chromatograficzne

62%

Kowalska T.

|

1998

|

tom R. 3, nr 3

8-10

14

Chromatografia cienkowarstwowa jako technika kontroli jakości surowców roślinnych

51%

Cieśla Ł. , Waksmundzka-Hajnos M.

|

2010

|

tom nr 2

54-58

PL

Ocena ilościowa składu surowca jest nieodłącznym elementem badania surowców farmakognostycznych, gdyż odpowiednia ilość określonych ciał czynnych zapewnia wartość leczniczą danego surowca.