Search results for "Thin-layer chromatography"

Chromatographic separation and partial identification of glycosidically bound volatile components of fruit

1990

Abstract Synthetic monoterpenic and aromatic β- d -glucosides and β- d -rutinosides were separated by Fractogel TSK HW-40 S chromatography according to their molecular size and interactions occurring between the aglycone moiety and the gel matrix. Under these conditions terpenyl rutinosides were eluted before the homologous glucoside derivatives. In the two classes, monoglucosides and rutinosides, aromatic glycosidically bound components had lower retention times than the corresponding terpenyl components. The use of over-pressure layer chromatography (OPLC) allowed the separation of glucoside and rutinoside derivatives, and in these two classes aromatic and several monoterpene compounds we…

Pharmacokinetics of triamterene after i.v. administration to man: determination of bioavailability.

1983

With a new formulation, which made intravenous infusion of triamterene (TA) possible, plasma levels and urinary excretion rates of TA and its main metabolite (OH-TA-ester) were measured in a randomized, cross-over trial in 6 healthy volunteers given triamterene 10 mg i.v. and 50 mg p.o. TA and OH-TA-ester were determined by densitometric measurement of native fluorescence after thin layer chromatography. Distribution volumes of the central compartment of TA and OH-TA-ester were 1.49 l/kg and 0.11 l/kg, respectively. Terminal half-lives were 255 min for TA and 188 min for OH-TA-ester after i.v. administration. For TA total plasma clearance was 4.5 l/min and renal plasma clearance 0.22 l/kg. …

MYCOTOXINS | Detection and Analysis by Classical Techniques

2014

This article is a revision of the previous edition article by Imad Ali Ahmed, volume 2, pp. 1526–1532, © 1999, Elsevier Ltd.

Inhibitoren der Korrosion (11). Nachweis der auf Eisengrenzflächen gebildeten Sekundärinhibitoren durch UV-Absorptions- und Fluoreszenzspektroskopie

1972

Aus Triphenylbenzylphosphoniumchlorid bildet sich in saurer Losung auf der Eisenoberflache eine Schicht, die aufgrund der UV-Reflexionsspektroskopie mit Triphenylphosphin identisch sein durfte. Auch das Mono- und Bis-Phosphoniumsalz wird an der Eisengrenzflache reduktiv abgebaut; die dabei entstehenden Anthracenderivate werden auf dieselbe Weise identifiziert. Es handelt sich um Methylanthracen. Die zur weiteren Aufgliederung der Reaktionsprodukte vorgenommene dunnschicht-chromatografische Auftrennung (Untersuchung des Extrakts in Cyclohexanol und Methanol) ergibt kein sich deutlich unterscheidenden Fluoreszenzspektren. Identification, by UV absorption and fluorescence spectroscopy, of the …

Synthesis of phenol–formaldehyde resole resins in the presence of tetraalkylammonium hydroxides as catalysts

2000

Abstract We synthesised phenol–formaldehyde resole resins in the presence of tetraalkylammonium hydroxides as catalysts. The activity of these catalysts was compared with the activity of sodium hydroxide. Gas chromatography, thin layer chromatography, 13 C NMR spectrometry, potentiometric titration and a few simple physicochemical methods were used to estimate the composition of the obtained resins and their properties. It was concluded from these studies that tetraalkylammonium hydroxides are active catalysts and the resins obtained in their presence show some interesting properties.

Authentication of phacelia honeys (Phacelia tanacetifolia) based on a combination of HPLC and HPTLC analyses as well as spectrophotometric measuremen…

2019

Abstract The growing interest in the quality of honey affects customer preferences and consumption trends. Generally, monofloral honeys are more expensive than multifloral honeys, and the price strictly depends on its botanical origin. The increasing popularity of a variety of monofloral brands has led to the increasing number of adulterations and therefore for the need to develop new analytical methods for assessing honey authenticity. The purpose of the present study was to develop a method for the authentication of phacelia honeys on the basis of HPLC and HPTLC analyses and spectrophotometry. The results obtained by spectrophotometric analysis indicated significant differences only betwe…

Polymere ester von säuren des phosphors, 4. Polymerisation des 2-äthoxy-2-oxo-4,5-dihydro-1,3,2-dioxaphosphorins

1976

Die ringoffnende Polymerisation des 2-Athoxy-2-oxo-4,5-dihydro-1,3,2-dioxaphosphorins (1) mit Alkoholaten als Initiatoren, ist durch folgende Merkmale gekennzeichnet: (a) Zur Polymerisation sind Temperaturen von uber 100°C und Reaktionszeiten von vielen Tagen erforderlich. (b) Es stellt sich ein Polymerisations-Depolymerisations-Gleichgewicht ein. Fur 125°C liegt der maximale Umsatz bei der Polymerisation in Substanz bei 70%. (c) Die Polymerisationsenthalpie hat den Wert 0±12,6 kJ mol—1 (0±3 kcal mol—1). (d) Es werden nur Oligomere gebildet. Die Ausbeute an Substanz mit Pn > 5 liegt um 3%. Die Oligomeren mit Pn = 1 bis 5 werden durch Dunnschichtchromatographie getrennt und durch Massenspekt…

Thin-layer chromatography of phenoxyacetic acid herbicides

1981

Synthesis and characterization of diatomaceous earth chemically modified with γ-aminopropyltrimethoxysilane

2003

A stationary phase for thin-layer chromatography has been prepared by bonding purified diatomaceous earth (rich in silica) with γ-aminopropyltrimethoxysilane. The phase has been characterized by elemental analysis, measurement of the specific surface area, IR spectroscopy, thermal analysis, and chromatographic testing.

Liquid chromatographic determination of planar aromatic sulphur compounds in crude oil

1989

Oxydation des dibenzothiophenes en sulfones et analyse par chromatographie liquide haute performance