Long optical path thin-layer spectroelectrochemistry in a liquid chromatographic ultraviolet-visible absorbance detector cell

1991 ◽  
Vol 63 (22) ◽  
pp. 2668-2672 ◽  
Author(s):  
Thomas R. Nagy ◽  
James L. Anderson
Keyword(s):  
Thin Layer ◽  
Optical Path ◽  
Detector Cell ◽  
Liquid Chromatographic

scholarly journals Biological Fingerprinting of Herbal Samples by Means of Liquid Chromatography

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Łukasz Cieśla
Keyword(s):  
Quality Control ◽  
Liquid Chromatography ◽  
Thin Layer ◽  
Published Data ◽  
Fingerprint Analysis ◽  
Chromatographic Techniques ◽  
Liquid Chromatographic ◽  
Further Development ◽  
Layer Chromatography ◽  
Chromatographic Fingerprinting

Biological chromatographic fingerprinting is a relatively new concept in the quality control of herbal samples. Originally it has been developed with the application of HPLC, and recently herbal samples' biological profiles have been obtained by means of thin-layer chromatography (TLC). This paper summarizes the application of liquid chromatographic techniques for the purpose of biological fingerprint analysis (BFA) of complex herbal samples. In case of biological TLC fingerprint, which is a relatively novel solution, perspectives of its further development are outlined in more detail. Apart from already published data, some novel results are also shown and briefly discussed. The paper aims at drawing scientists' attention to the unique solutions offered by biological fingerprint construction.

Colorimetric and Gas-Liquid Chromatographic Determination of Atropine-Hyoscyamine and Hyoscine (Scopolamine) in Solanaceous Plants

1975 ◽  
Vol 58 (5) ◽  
pp. 884-887
Author(s):  
Mohamed S Karawya ◽  
Samia M Abdel-Wahab ◽  
Mohamed S Hifnawy ◽  
Mohamed G Ghourab
Keyword(s):  
Citric Acid ◽  
Acetic Anhydride ◽  
Thin Layer ◽  
Chromatographic Determination ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic Determination ◽  
Solanaceous Plants ◽  
Liquid Chromatographic ◽  
Colorimetric Methods

Abstract Two colorimetric micromethods are described for the determination of atropine-hyoscyamine and hyoscine (scopolamine), using p-dimethylaminobenzaldehyde and citric acid-acetic anhydride as the color reagents. These methods are sensitive to 60-1200 and 10-360 μg alkaloid/10 ml. The colorimetric methods were also successfully applied after a preliminary thin layer chromatographic separation of the alkaloids. A gasliquid chromatographic procedure was also developed, which yielded comparable results with the colorimetric methods.

scholarly journals Rapid Identification and Quantitation of Clotrimazole, Miconazole, and Ketokonazole in Pharmaceutical Creams and Ointments by Thin-Layer Chromatography–Densitometry

1996 ◽  
Vol 79 (3) ◽  
pp. 656-660 ◽  
Author(s):  
Utpal Roychowdhury ◽  
Saroj K Das
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Uv Light ◽  
Internal Standard ◽  
Solvent System ◽  
Short Wave ◽  
Rapid Identification ◽  
Pharmaceutical Creams ◽  
Liquid Chromatographic ◽  
Layer Chromatography

Abstract Thin-layer chromatography (TLC)–densitometry was used to separate, identify, and quantitate clotrimazole, miconazole, and ketokonazole (alone or combined with other drugs) in various pharmacopoeial or proprietary creams and ointments. Clotrimazole was extracted from the cream or ointment with ethyl alcohol, and miconazole and ketokonazole were extracted with a mixture of equal volumes of chloroform and isopropyl alcohol. Active ingredients were separated from excipients and other drugs by TLC on a precoated silica gel F254 plate with a solvent system of n-hexane–chloroform–methanol–diethylamine (50 + 40 + 10 + 1, v/v). The 3 azoles were well separated and easily identified in this chromatographic system. The separated azoles were visualized under short-wave UV light and quantitated by scanning densitometry at 220 nm by comparing the integrated areas of samples with those of standard (one azole was used as internal standard for the other). Recoveries from samples spiked with known amounts of azoles were excellent. The method was validated further by comparison with official liquid chromatographic methods.

Comparison of Radioimmunoassay with Thin-Layer Chromatographic and Gas—Liquid Chromatographic Methods of Barbiturate Detection in Human Urine

1975 ◽  
Vol 21 (6) ◽  
pp. 672-675 ◽  
Author(s):  
David L Roerig ◽  
Donna L Lewand ◽  
Marilyn A Mueller ◽  
Richard I H Wang
Keyword(s):  
Thin Layer ◽  
Human Urine ◽  
False Positives ◽  
Urine Samples ◽  
Chromatographic Methods ◽  
Large Numbers ◽  
Excellent Method ◽  
Liquid Chromatographic

Abstract A radioimmunoassay (I) for barbiturates was compared with thin-layer chromatographic (II) and gas—liquid chromatographic (III) methods for barbiturate detection in human urine. Timed urine samples were obtained from volunteers who had ingested 100 mg of a barbiturate. I detected barbiturate in all urines tested up to 76 h after the dose, and III in all up to 52 h and in 90% up to 76 h. II detected barbiturates in 90% of all urine samples for only 30 h, after which its reliability declined. Glutethimide interfered with radioimmunoassay of barbiturate, producing false positives. I is sensitive, reliable, and fast, and lends itself to screening large numbers of urine samples for barbiturates. For routine urine surveillance, however, we found I to be less useful than II, which is still the method of choice. I has, however, proved to be an excellent method for confirming resuits of II.

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