scholarly journals Synthesis of 4-aryloxy-7-nitrobenzofurazan derivatives from 4-chloro-7-nitrobenzofurazan and various phenoxide anions (including pharmaceuticals) in the presence of crown ethers

2003 ◽  
Vol 1 (3) ◽  
pp. 260-276 ◽  
Author(s):  
Marioara Bem ◽  
Miron Caproiu ◽  
Dan Stoicescu ◽  
Titus Constantinescu ◽  
Alexandru Balaban
Keyword(s):  
Thin Layer ◽  
Nucleophilic Substitution ◽  
Thin Layer Chromatography ◽  
Crown Ethers ◽  
Nmr Spectra ◽  
Reverse Phase ◽  
Layer Chromatography

Abstract4-Chloro-7-nitrobenzofurazan reacts by nucleophilic substitution with phenoxide anions derived from estriol (2c), ethynylestradiol (2d), phenol (3e), guaiacol (3f), 2,6-dimethoxyphenol (3g), eugenol (3h), isoeugenol (3i), the cytostatic Etoposide (4), and Reichardt’s betaine (5) in the presence of crown ethers affording the corresponding 4-aryloxy-7-nitrobenzofurazan derivatives 6c, 6d, 7e-7i, 8, and 9. The structure of these compounds was confirmed by NMR spectra. Hydrophobicity/hydrophilicity parameters were investigated by reverse phase thin-layer chromatography.

Separation of Barbiturates Using Reverse-Phase Thin-Layer Chromatography

1980 ◽  
Vol 16 (2) ◽  
pp. 219-221 ◽  
Author(s):  
William Bress ◽  
Kenneth Ziminski ◽  
Walter Long ◽  
Thomas Manning ◽  
Leslie Lukash
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Reverse Phase ◽  
Layer Chromatography

scholarly journals Reverse Phase Thin Layer Chromatography of Aminoalkanethiosulfuric Acids, Mercaptoalkanamines and Aminoalkyl Disulfides

2002 ◽  
Vol 3 (7) ◽  
pp. 755-763 ◽  
Author(s):  
Maria Das Graças Cardoso ◽  
David Nelson ◽  
Antônia Tavares do Amaral ◽  
Custódio Dos Santos ◽  
Alcilene De Abreu Pereira ◽  
...  
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Reverse Phase ◽  
Layer Chromatography

Quantitation of Ochratoxin A: Use of Reverse Phase Thin-Layer Chromatography for Sample Cleanup Followed by Liquid Chromatography or Direct Fluorescence Measurement

1988 ◽  
Vol 71 (5) ◽  
pp. 949-953 ◽  
Author(s):  
Andrzej A Frohlich ◽  
Ronald R Marquardt ◽  
Aniko Bernatsky
Keyword(s):  
Liquid Chromatography ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Ochratoxin A ◽  
Uv Light ◽  
Packed Column ◽  
Fluorescence Measurement ◽  
Reverse Phase ◽  
Direct Fluorescence ◽  
Layer Chromatography

Abstract An improved procedure for sample preparation and quantitation of ochratoxin A in moldy grain was developed. Grain samples were acidified and extracted, and extracts were subjected to reverse phase thin-layer chromatography (RPTLC). The separated spots, which were identified under UV light, were scraped and collected into recovery devices. Ochratoxin A was eluted from the adsorbent and analyzed by either liquid chromatography with fluorescence detection or direct spectrofluorometric measurement. The method yielded values that were proportional to the concentrations of toxin in the sample, had relatively high levels of recovery (94%), and required considerably less volume of solvents and preparation time than a standard packed column method.

scholarly journals A Rapid, Sensitive Thin Layer Chromatography Procedure for the Detection of Fumonisin B1 and B2

1992 ◽  
Vol 4 (3) ◽  
pp. 326-329 ◽  
Author(s):  
George E. Rottinghaus ◽  
Charles E. Coatney ◽  
Harry C. Minor
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Fumonisin B1 ◽  
Sodium Borate ◽  
Reverse Phase ◽  
University Of Missouri ◽  
Tlc Plates ◽  
Green Fluorescent ◽  
Sodium Borate Buffer ◽  
Layer Chromatography

A thin layer chromatography (TLC) method was developed for the detection of fumonisin B1 and B2 in corn and corn-based feedstuffs. Finely ground samples were extracted with acetonitrile: water (1: 1), filtered, and applied to C18 cleanup columns. The columns were washed with 1% aqueous KCl followed by acetonitrile: 1% aqueous KC1 (1:9), and the fumonisins were eluted with acetonitrile: water (7:3). The eluants were concentrated and spotted on reverse-phase C18 TLC plates along with fumonisin B1 and B2 standards, and the plates were developed in methanol: 4% aqueous KCl (3:2). The fumonisins were visualized by spraying the TLC plates successively with 0.1 M sodium borate buffer, fluorescamine, and 0.01 M boric acid. The plates were then dried and examined under longwave ultraviolet light. Fumonisin B1 and B2 appeared as bright yellowish-green fluorescent bands at Rfs of 0.5 and 0.1, respectively. The detection limit for the fumonisins on the TLC plate was 0.1 ppm in corn. Recoveries from spiked samples averaged >80%. The identification of the fumonisins was confirmed by hydrolyzing the parent compounds of B1 and B2 to their respective C22 amino-alcohols and reexamining by TLC with the same visualizing reagents. This procedure was used to survey 193 corn samples collected from University of Missouri test plots in 1990 for fumonisin B,. Fumonisin B1 was detected in 15% of the corn samples.

scholarly journals identification of phylloquinone in cattle samples using T.L.C. method

2010 ◽  
pp. 75-78
Author(s):  
Lucian Bara
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Mass Spectroscopy ◽  
Vitamin K ◽  
Direct Method ◽  
Unknown Origin ◽  
Reverse Phase ◽  
Tlc Plates ◽  
Layer Chromatography

A case of hemorrhage of unknown origin was observed in cattle and liver samples were submitted for assay of Vitamin K orpossible cuomarol. After evaluating normal and reverse phase Thin Layer Chromatography (TLC) plates and different solvents,reverse phase TLC plate with indicator and methylene chloride:methanol 70:30 were chosen for direct method of detection andindication of Vitamin K.Gass Chromatography and Densitometry were used to quantitate the Vitamin K present in liver samples andconfirmation of Vitamin K was done by Mass Spectroscopy.

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