Macherey Nagel

The first observation of the enantioselective properties of an albumin was made in 1958 (28) when it was discovered that the affinity for L-tryptophan exceeded that of the D-enantiomer by a factor of approximately 100. This led to more studies in 1973 of the separation of DL-tryptophan [54-12-6] C22H22N2O2, on BSA immobilized to Sepharose (29). After extensive investigation of the chromatographic behavior of numerous racemic compounds under different mobile-phase conditions, a BSA-SILICA hplc column (Resolvosil-R-BSA, Macherey-Nagel GmvH, Duren, Germany) was... 

Alumina was purchased from Macherey, Nagel and Co., Diiren (FRG). The checkers employed 650 g of neutral alumina (Fisher, adsorption grade, 80-200 mesh) packed in a 40-cm high column. Yellow impurities remained on the column, while the blue azulene came off with the hexane solvent front. 

The progress of the reaction may be followed by analytical thin-layer chromatography on alumina. The submitters used polygram pre-coated plastic sheets (Alox N/UV254) purchased from Macherey-Nagel, Inc. The plates were developed with 1 1 hexane-ether and stained with basic permanganate. The Rf of the product is 0.56. 

Polyamide is available commercially as polyamide-6 (based on e-aminocapro-lactam, Macherey-Nagel) and as polyamide-11 (based on 11-aminoundecanoic acid, Merck). The lipophilic properties of these are different, thus altering their chromatographic selectivity. 

Differences in the materials employed for the layers can also become evident when chemical reactions are performed on them. Thus, Macherey-Nagel report that the detection of amino acids and peptides by reaction with ninhydrin is less sensitive on layers containing luminescent or phosphorescent indicators compared to adsorbents which do not contain any indicator [7]. 

The fact that the binder used in the layer can affect the reagent is shown in the monograph on 4-(4-Nitrobenzyl)pyridine reagent. It is not possible to employ this reagent on Nano-SIL C 18-100 UV254 plates (Macherey-Nagel) because the whole surface of the layer is colored bluish-violet. The corresponding water-wettable layers produced by the same manufacturer do not present any difficulties. 

MACHEREY-NAGEL Company literature, Jirtigproduktefiir die Dunnschicht-Chromato-graphie", 1985. 

TLC plates Silica gel 60 W or HPTLC plates Silica gel 60 WRp254s (Merck) SIL G-25 or Nano-Sil-20 (Macherey-Nagel). 

Note If the spray solution or a nonbasic dipping solution is employed for detection then it is advisable to spray afterwards with a 10% aqueous solution of sodium carbonate or a 2% solution of borax in ethanol — water (1 + 1). It is often possible to achieve the required basicity by placing the chromatogram in a twin-trough chamber one of whose troughs contains 5 ml 25% ammonia. This is not suitable for the Chiralplate (Macherey-Nagel) because in this case the plate background acquires a dark violet coloration. 

The reagent can be employed on sihca gel, kieselguhr. Si 50 000, cellulose, CN and RP layers. NH2 layers are unsuitable, since no coloration is produced, as are Nano-SIL Cl8 UV254 plates (Macherey-Nagel), since the whole plate background is colored violet. 

We thank the Baron, J. T. Baker, Camag, Desaga, Macherey-Nagel and E. Merck companies for their generous support of the experimental work. 

NucleosilChiral-I L-hydroxyproline Cu- complexes bonded on silica gel [33] Macherey-Nagel... 

MACHEREY-NAGEL Company literature. J rtigprodukle fiir die DUnnschicht-Chromatographie", 1985. 

Macherey-Nagel Silica P/UV254 with Gypsum 60 6... 

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