Identifizierung von Aminen

Zusammenfassung 4-Dimethylamino-3,5-dinitrobenzoyl-Derivate von Aminen (DADB-Amine) verschiedener chemischer Struktur wurden dünnschicht-chromatographisch und massenspektrometrisch untersucht. Die Fragmentierung dieser Verbindungen bei Elektronenbeschuß wird diskutiert. Aus den Massenspektren der DADB-Amine kann die Struktur eines unbekannten Amins weitgehend abgeleitet werden. In einzelnen Fällen, z.B. bei manchen iso- und n-Alkylaminen, sind zusätzliche NMR-Messungen nützlich. Die Massenspektrometrie erlaubt, besonders in Kombination mit der Dünnsehicht-Chromatographie, unbekannte Amine in komplexen Gemischen schnell und sicher zu identifizieren.

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Identification of aminesIII. Thin-layer chromatography and mass spectrometry of 4-dimethylamino-3,5-dinitrobenzoyl derivatives (DADS-amines)

4-Dimethylamino-3,5-dinitrobenzoyl derivatives of amines (DADB-amines) having different chemical structures were examined via thin-layer chromatography and mass spectrometry. The fragmentation of these compounds due to electron bombardment is discussed. On the basis of mass spectra of the DADB-amines, the structure of an unknown amine can be derived to a great extent. In some cases, e.g. many isoand n-alkyl amines, additional NMR-measurements are usefull. Mass Spectrometry makes it possible, particularly in combination with thin-layer chromatography, to identify unknown amines in complex mixtures rapidly and accurately.

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Teil I: diese Z. 247, 155 (1969). Teil II: diese Z. 247, 158 (1969).

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Auszugsweise vorgetragen: Hauptversammlung GDCh, Karlsruhe, September 1971.     

Identifizierung von Aminen

2,4-Dinitrophenyl derivatives of amines (DNP-amines) were investigated by thin-layer chromatography and mass spectrometry. The fragmentation of the compounds upon electron impact is discussed. The investigations show that amines in their form as DNP-derivatives can be separated by TLC except for some critical pairs. From the mass spectra of the DNP-amines the structure of an amine can be elucidated so far that a quick and reliable identification is possible by comparison with authentic material and IR spectroscopy.     

New solvent systems for thin-layer chromatographic determination of nine biogenic amines in fish and squid

Different solvent systems were evaluated for their ability to separate biogenic amines by thin-layer chromatography (TLC). Dansyl derivatives of agmatine, putrescine, tryptamine, cadaverine, spermidine, histamine, spermine, tyramine and beta-phenylethylamine were separated using the solvent system chloroform-diethyl ether-triethylamine (6:4:1), followed by chloroform-triethylamine (6:1). After separation dansyl amines were quantified by fluorescence densitometry at 330 nm. Correlation coefficients of linear regressions were higher than 0.99 for all amines, except for agmatine (0.976). Detection limits were 10ng for tryptamine, tyramine, histamine and beta-phenylethylamine, and 5 ng for the other amines. The overall repeatability of the chromatography was 1.82% when including agmatine and barely 1.02% for the other amines. The accuracy ranged from 105.97% (agmatine) to 49.92% (tryptamine). This thin-layer chromatography method was found to be an effective and precise analytical procedure to separate and determine biogenic amines. Its main advantages compared to previous procedures are that it uses less harmful solvent (diethyl ether instead of benzene) and can separate a larger group of biogenic amines.     

The application of triphenylmethane dyes to visualization of selected aliphatic compounds in thin-layer chromatography

Selected triphenylmethane dyes were used as new visualizing agents in thin-layer chromatography of higher fatty acids, higher fatty alcohols, and higher aliphatic amines.     

Direct analysis of thin-layer chromatograms and electrophoretograms by secondary ion mass spectrometry

Mixtures separated by thin-layer chromatography and electrophoresis can be analyzed in situ by secondary ion mass spectrometry. The paramount advantage of such a combination is the selectivity inherent to the mass spectrum, which can provide information sufficient for the identification of an unknown compound as well as precise quantification of known compounds. Separation of the time frames of chromatographic development and mass spectrometer operation relaxes the constraints on each, and unique analytical advantages result.     

Identifying N-nitrosofenfluramine in a nutrition supplement

The analytical data for identifying an unknown substance that was found in a nutrition supplement is presented. The unknown substance is purified using thin-layer chromatography and then measured using high-resolution mass spectrometry (HRMS) giving the exact mass from which the structure of the unknown substance was proposed. The procedure for synthesizing N-nitrosofenfluramine from fenfluramine is described. The extracted, synthesized, and standard N-nitrosofenfluramine are compared using HRMS, high-performance liquid chromatography (HPLC)-MS, HPLC-UV, Fourier transform IR spectroscopy, gas chromatography-MS, TLC, and NMR (1H NMR and 13C NMR). All analytical data obtained confirm that the unknown peak in the nutrition supplement is N-nitrosofenfluramine and that the synthetic procedure described can easily provide the N-nitrosofenfluramine reference substance for identification.     

Thin-Layer Chromatography of Metal Cations Modified with Amines and Surfactants and the Sorption-Catalytic Detection of Cobalt(II) and Copper(II)

JPC – Journal of Planar Chromatography – Modern TLC - The thin-layer chromatography (TLC) procedures of metal cations, modified with amines and cationic surfactant micelles, followed by...     

High-performance liquid chromatography – atmospheric pressure negative chemical ionisation – mass spectrometry of 2,4-dinitrophenyl derivatives of amines

High-performance liquid chromatography (HPLC) coupled to mass spectrometry (MS) is used to detect 2,4-dinitrophenyl (DNP) derivatives of amines by means of negative chemical ionisation at atmospheric pressure. The high sensitivity and good comparability of UV- and MS-detection of DNP-derivatives of amines is shown by several examples. The high selectivity of the derivatisation and the detection method (UV and MS) is used for the analysis of unknown amines in aqueous phases after hydrolytic degradation of polyamide-amine- or polyamine-epoxide-adducts as well as for the characterisation of commercial products.     

Identifizierung von Aminen

Zusammenfassung 2,4-Dinitrophenylderivate von Aminen (DNP-Amine) werden dünnschicht-chromatographisch und massenspektrometrisch untersucht. Die Fragmentierung der Verbindungen bei Elektronenbeschuß wird diskutiert.Die Untersuchungen zeigen, daß Amine als DNP-Derivate bis auf einige kritische Paare dünnschicht-chromatographisch getrennt werden können. Aus den Massenspektren der DNP-Amine kann die Struktur eines Amins so weit ermittelt werden, daß durch Vergleich mit authentischem Material und IR-Spektroskopie eine rasche und sichere Identifizierung möglich ist.

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Identification of aminesI. Thin-layer chromatography and mass spectrometry of 2,4-Dinitrophenyl derivatives (DNP-amines)

2,4-Dinitrophenyl derivatives of amines (DNP-amines) were investigated by thin-layer chromatography and mass spectrometry. The fragmentation of the compounds upon electron impact is discussed.The investigations show that amines in their form as DNP-derivatives can be separated by TLC except for some critical pairs. From the mass spectra of the DNP-amines the structure of an amine can be elucidated so far that a quick and reliable identification is possible by comparison with authentic material and IR spectroscopy.

     

Activated alpha-alkyl-alpha-arylacetic acid enantiomers for stereoselective thin-layer chromatographic and high-performance liquid chromatographic determination of chiral amines

The separation of racemic benoxaprofen into the two benoxaprofen enantiomers by preparative high-performance liquid chromatography and the application of the activated enantiomers as derivatization reagents for the simultaneous stereoselective determination of chiral amines in biological material is described. Activated (+)- and (-)-benoxaprofen are both shown to be very sensitive and stable chiral fluorescence markers, applicable to thin-layer chromatography as well as to high-performance liquid chromatography.     

Determination of the 7-amino-metabolites of the 7-nitro-benzodiazepines in human plasma by thin-layer chromatography

A sensitive thin-layer chromatographic method is described for the determination of the 7–amino-metabolites of flunitrazepam and clonazepam. The same procedure is applicable to other 7-nitro-benzodiazepines such as nitrazepam. A purified plasma extract of the 7-amino-metabolites is separated by thin-layer chromatography. The primary aromatic amines are diazotized and coupled with N-(1-naphthyl) ethylene-diamine on the thin-layer plate. The quantities of the 7-amino-metabolites are directly evaluated by colorimetric densitometry. The lower limit of detection is in order of 0.5–10 ng cm^?3 of plasma. The relative standard deviation of the whole procedure is less than ±15% in the range of 0.5–10 ng cm^?3 for a single determination. The unchanged drugs can be reduced on the thin-layer plate and detected by the same method. Since this procedure is rather difficult to perform, it is advantageous to determine the 7-nitro-benzodiazepines in plasma by gas chromatography. The thin-layer chromatographic method was used to measure the 7-amino-metabolites in plasma of patients on either a flunitrazepam or a clonazepam oral dosing regimen.     

Studies on Fluorescamine. Part II - Thin-Layer Chromatographic Mobilities of Fluorescamine Positive Drugs

Abstract

Fluorescamine reacts with primary amines, it does not react with secondary or tertiary amines, to yield bright acquamarine fluorescent products. This reaction has been developed into a spot test useful for differentiation of amphetamine from methamphetamine; previous spot tests did not have this degree of specificity. The fluorescent products of several primary amines have been demonstrated to have sufficient stability to permit thin-layer chromatography comparisons with authentic materials. The fluorescent derivative of amphetamine has been demonstrated to be capable of differentiation from other fluorescent products formed from fluorescamine based on its unique migration in three different TLC systems.     

Chromatographic determination of morpholine and products of its microbiological degradation

A combination of thin-layer chromatography (TLC) with high-performance liquid chromatography (HPLC) was shown to be efficient in determining the intermediate products of the utilization of thiomorpholine with ligninolytic basidiomycete fungus Bjerkandera adusta VKM F-3477. The chromatographic mobility of the products of microbiological degradation of thiomorpholine was studied on Sorbfil PTSKh-P-V plates in the systems of chloroform-methanol-25% aqueous ammonia (80: 20: 2) for determining cyclic amines and isopropanol-25% aqueous ammonia (70: 30) for determining thio acids. The optimum conditions were selected for the separation of thiomorpholine and the formed metabolites by ion-exchange chromatography and reversed-phase chromatography.     

Thin-layer chromatography of low-molecular epoxy compounds after derivatization with picric acid

Summary Optimum conditions were obtained for the determination of low-molecular epoxides by a method based on derivatization with picric acid and thin-layer chromatography on silica gel. The chromatograms were visualized with solutions of primary, secondary or tertiary amines in acetone. Most of the monoepoxides gave only one spot; diepoxides gave two spots. The detection limits for highly reactive epoxy compounds (derivatization time less than 2 hours) were estimated to be approx. 0.02 μmole.     

Effect of Salt and pH on the Hydrophobicity of Some Basic Ion-Pairing Agents

Abstract

The lipophilicity (hydrophobicity) of some alkyl and arylamines was determined with reversed-phase thin-layer chromatography using water:methanol 1:1 v/v eluent with salt and various buffers added to the system. The effect of various structural parameters of amines and that of the chromatographic conditions were assessed with stepwise regression analysis. Both salt concentration and pH influenced the lipophilicity of amines decreasing linearly with increasing salt concentration and pH. The lipophilicity values of alkylamines extrapolated to 0 pH showed a very low dependence on the length of alkyl chain. The PH sensitivity of alkylnmines depended linearly on the length of alkyl chain.     

Application of Thin-Layer Chromatography and Gas Chromatography—Mass Spectrometry for Evaluation of the Chemical Stability of Hexyl Nicotinate

JPC – Journal of Planar Chromatography – Modern TLC - In this study, thin-layer chromatography with densitometry and gas chromatography—mass spectrometry (GC—MS) were used...     

Effect of Chamber Gas Phase on Mobile Phase pH and on Separation Efficiency in TLC. A New Mode of Chromatography

A new variant of thin-layer chromatography (TLC), based on a gradual change of mobile phase acidity during elution, is proposed. The pH change occurs in the mobile phase moving along the TLC plate as a result of its contact with an acidic or a basic gas phase that replaces the initial mobile phase vapor in the TLC chamber. The potential of this approach has been demonstrated by using carbon dioxide and ammonia gases to improve the resolution of benzoic acids and aromatic amines on polyamide TLC plates.     

Artifacts produced by using dichloromethane in the extraction and storage of some antihistaminic drugs.

The use of dichloromethane for the extraction of amines may lead to the formation of artifacts. Dichloromethane reacts rapidly (37.5 degrees) with brompheniramine, diphenylpyraline, cyclizine, cyproheptadine but not with antazoline and lignocaine. This difference in reactivity as well as the thin-layer chromatographic, gas-liquid chromatographic, nuclear magnetic resonance, and mass spectrometric characteristics of cyclizine and diphenylpyraline chloromethochlorides are investigated.