R. L. Munier

Simultaneous separation of 1-dimethylamino-5-naphthalenesulfonyl amino acids and 2,4-dinitrophenyl amino acids by two dimensional thin-layer chromatography on cellulose powder

SummarySeparation procedure and positions of 46 dinitrophenylamino acids and dimethylaminonaphtalene sulfonylaminoacid spots obtained by thin-layer chromatography on cellulose powder are described. Separation methods previously described for dinitrophenylamino acids [1,3,4] and dansylaminoacids [2] are used.

Two-dimensional separations and behaviour of alkaloids of various polarities on unmodified silica gel in polar and very polar neutral or acidic mobile phases

SummaryNew separation procedures for alkaloids of similar polarity and structure or of very different polarity and structure, based upon two-dimensional thin-layer chromatography on unmodified silica gel under mild conditions are described. Separation factors and separation mechanisms based on the structure of the bases and mobile phase composition are discussed for some examples of very efficient procedures.

Two-dimensional separations and behaviour of Rauwolfia, Corynanthe and Pseudocinchona alkaloids on unmodified silica gel

SummaryVery efficient procedures for separation by TLC in mild conditions of fifteen alkaloids of the Rauwolfia, Corynanthe, Pseudocinchona group are described. Questions relating to the appaent selectivity of separation systems and separation factors in polar or very polar neutral or acidic mobile phases are discussed.

Separation of amino acids. Possibilities offered by optimized associations of low-voltage electrophoresis and chromatography on finely textured paper and on cellulose thin-layers

SummaryThree optimized small-scale methods for amino acid separation are described and compared. Two dimensional separations are based on paper or cellulose thin-layer ionophoresis and chromatography with simple and inexpensive apparatus. The influence of experimental conditions on resolution and amount required for amino acids possessing almost identical mobilities, is studied. The quickest procedure based on the coupling of 200×200×0.25 mm thin-layer, low-voltage electrophoresis (20 V/cm) with chromatography, and the system: cellulose −1.04 mol dm−3 formic acid — tertbutanol/methanol/pyridine/formic acid/water (33∶43∶9.6∶0.4∶20), provides very reproducible results with high separating power for small samples (2–10 nmoles).

New chromogenic reagents for labelling amino groups in peptides. Chromatographic and preparatives aspects

SummaryA new type of chromogenic reagent for labelling the amino groups of peptides or amino acids, 5-substituted 2,4-dinitrofluorobenzenes, is presented. These reagents are characterized by a polarity determined by the function included in the substituent in the 5-position and by the nature of this substituent. Preparation and chromatographic behaviour of these reagents, of eventual by-products of reactions and of some N-(2,4-dinitro-5-diethylaminophenyl)-peptides or amino acids are described.

Some effective solvents for rapid and reliable characterization of phenylthiohydantoin-amino acids

SummaryOne-dimensional chromatography with internal standards permits reliable identification of the phenylthiohydantoins from all the common amino acids with the following TLC systems: silica gel — “chloroform”/n-butyl acetate (90∶10), di-isopropylether/ethanol (95∶5), dichloromethane/ethanol/acetic acid (90∶8∶2) ortrans-dichloroethylene/ethanol/acetic acid (88∶10∶2); and cellulose with 25% formic acid — heptane/isobutanol/75% fromic acid (40∶30∶9) or silica gel — “chloroform”/ ethanol/acetic acid/water (50∶47∶0.5∶2.5).