Oxalic acid dihydrate as a green, mild and efficient catalyst for the one-pot three-component Biginelli synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives from the reaction between β-keto esters (methyl or ethyl acetoacetate), aromatic aldehyde (benzaldehye derivatives) and urea or thiourea under thermal and solvent-free conditions with excellent yields and short reaction time is st...

The cellulose ion exchangers (1) have proved to be useful chromatographic media for the serum proteins. In the fractionation of normal human serum on the anion exchanger, diethylaminoethyl (DEAE) cellulose, application of buffer gradients of increasing concentration and decreasing pH results in the appearance of components in the effluent fluid in order of increasing electrophoretic mobility (2...

We report the results of experimental work focusing on host-guest supramolecular complex creation between macrocyclic compound (β-cyclodextrin) and 1-acenaphthenol enantiomers (racemic mixture) in liquid phase composed of 35% acetonitrile in water (v/v) at different temperatures ranging from 0 to 90 °C. Experimental setup involved several analytical protocols based on classical non-forced flow ...

Chromatographic system for simultaneous determination of levodopa, biogenic amines, and methylxanthines in food has been developed. Chromatographic column and precolumn with octadecylsilane phase and simultaneously fluorescence and DAD detectors have been used. Gradient elution with acetate buffer (pH=4.66) with acetonitrile has been applied. Examination included levodopa, norepinephrine, dopam...

This work is concerned with the development and validation of two accurate, precise and specific spectrophotometric and chromatographic methods for analysis of Phenylepherine (PE), Lidocaine (LC) and Thiomersal (TM) in their ternary mixture and in Chromoderm® solution. The developed spectrophotometric method is the mean centering of ratio spectra (MCR) spectrophotometric method that depends on ...

Ion-exchange chromatographic analysis of peroxynitric acid (O2NOOH) was performed by combining an acidic eluate with an UV-vis detector and immersing the separation column in an ice-water bath. The decomposition behavior of peroxynitric acid in the solution was also studied using this system. The fraction for the peroxynitric acid peak was collected. Ion-exchange chromatographic analysis of thi...

1. Azopigments derived from conjugated bile pigments by coupling with the diazonium salt of ethyl anthranilate are analysed conveniently by quantitative t.l.c. or by column chromatography on CM-cellulose. 2. By chromatographic studies combined with a series of chemical tests six groups of azopigments were demonstrable in preparations from bile and from icteric urine of man. Azobilirubin and its...

This article describe the applicability of 1,4-disulfopiperazine-1,4-diium chloride ([Piper-(SO3H)2].2Cl) as a green, versatile and Brönsted acidic ionic catalyst in the promotion of the synthesis of phthalazine derivatives via one-pot three component reaction between aromatic aldehydes, 1,3-diketone derivatives and phthalhydrazide under solvent-free reaction cond...

The potential for using polyelectrolyte multilayers (PEMs) to provide chromatographic functionality on continuous silica networks created from sol-gel chemistry has been evaluated by capillary electrochromatography (CEC). Construction of the PEM was achieved by flushing the column with polyelectrolytes of alternative charge, with variation of the properties of the exposed polyelectrolyte provid...

The chromatographic behavior of some basic and acidic drugs was studied on C18, Phenyl-Hexyl and Polar RP columns with methanol or acetonitrile as organic modifiers of aqueous mobile phases containing addition of diethylamine. Diethylamine plays a double function of silanol blocker reagent in analysis of basic drugs and ion-pair reagent in analysis of acidic drugs. Most symmetrical peaks and hi...