An important property that has been extensively studied in quantitative structure activityrelationship (QSAR) is the chromatographic retention index. QSAR study is suggested for theprediction of retention index of alkanes and alkenes compounds. Modeling of the retention indexof alkanes and alkenes compounds as a function of molecular structures was established bydifferent chemometrics methods. ...

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...

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...

Static light-scattering (LS) detection can determine the molecular weight (MW) of polymers eluted with size-exclusion chromatography (SEC) without using any standards when the differential refraction index (RI) of solutes are obtained. On the other hand, the noisy chromatographic signal peak acquired using a static LS detector often causes difficulty in peak-width recognition. This disadvantage...

We report a method for the purification of plastoquinone-9 (PQ), a prenylquinone cofactor involved in the photosynthetic electron transport chain. The described procedures relies on spinach-chloroplast isolation followed by PQ extraction and chromatographic fractionation. Extraction of PQ was achieved using partition of chloroplast suspension with methanol:petroleum ether. This procedure remove...

We have developed an accurate and highly sensitive gas-chromatographic/mass-spectrometric procedure for determining di- and polyamines (putrescine, spermidine, and spermine) in plasma and erythrocytes. Deuterium-labeled analogs of putrescine, spermidine, and spermine were synthesized for use as internal standards. Trifluoroacetyl derivatives of the polyamines were formed during the procedure an...

In commonly used procedures for colorimetric assay of orotic acid in biological materials, certain substances interfere, positively or negatively. Some that interfere negatively are ornithine, cysteine, citrulline, tyrosine, proline, hydroxyproline, and polyamines. Protein and interfering agents are easily removed by first isolating the total organic acid fraction. The orotic acid in this fract...

A procedure is described to utilize blue dextran-Sepharose as an affinity chromatographic column specific for the super-secondary structure called the dinucleotide fold, which forms the binding sites for substrates and effectors on a wide range of proteins. The procedure can be used to identify proteins, either purified or in crude cellular extracts, that possess the dinucleotide fold and to si...

We describe a practical, technically convenient DEAE-Sephadex chromatographic column and a three-fraction salt-gradient elution procedure, with which serum creatine kinase activity is rapidly and quantitatively separated into the isoenzyme components with excellent analytical recovery of the total activity applied. The homogeneity of the isoenzyme fractions was demonstrated by electrophoresis a...

A sensitive gas-liquid chromatographic assay for sobrerol in biological fluids has been developed. The assay procedure involves esterification of both hydroxyl groups of sobrerol with pentafluoropropionic anhydride to form the diester which can be quantitated using gas-liquid chromatography-electron-capture detection. The detection limit of plasma sobrerol under the conditions described is 5 ng...