Identification of the aromatic hydroxylamine group by mass spectrometry

The mass spectra of aromatic hydroxylamines are diagnostic; [M], [M – 2], [M – 16] and, in most instances, [M – 17] ions are observed.     

Erratum to: Analysis of the Yperite Block Fished up from the Baltic Sea

JPC – Journal of Planar Chromatography – Modern TLC -     

Preparation of optically active cyclohexenones: Chirons for the lipophilic moiety of flowery- and woody-like odorant ketones

Optically active 2,5,6,6- and 2,4,4,5-tetraalkylcyclohex-2-en-1-ones ((+)- 2a – d and (?)- 5a – d ), important building blocks for flowery- and woody-like odorants, have been prepared. Compounds (+)- 2a – d and (?)- 5a – d were obtained by ozonolysis of the corresponding cyclopentenic precursors, followed by intramolecular aldol condensation. Alternatively, enones (+)- 2a – d were reduced to the corresponding allylic alcohols ad converted to enones (-)- 5a – d via acidic isomerization and oxidation. ¹³C-NMR assignments are presented.     

Laser-Induced Hydrogen Radical Removal in UV MALDI-MS Allows for the Differentiation of Flavonoid Monoglycoside Isomers

Negative-ion matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectra and tandem mass spectra of flavonoid mono-O-glycosides showed the irregular signals that were 1 and/or 2 Da smaller than the parent deprotonated molecules ([M – H]^–) and the sugar-unit lost fragment ions ([M – Sugar – H]^–). The 1 and/or 2 Da mass shifts are generated with the removing of a neutral hydrogen radical (H*), and/or with the homolytic cleavage of the glycosidic bond, such as [M – H* – H]^–, [M – Sugar – H* – H]^–, and [M – Sugar – 2H* – H]^–. It was revealed that the hydrogen radical removes from the phenolic hydroxy groups on the flavonoids, not from the sugar moiety, because the flavonoid backbones themselves absorb the laser. The glycosyl positions depend on the extent of the hydrogen radical removals and that of the homolytic cleavage of the glycosidic bonds. Flavonoid mono-glycoside isomers were distinguished according to their TOF MS and tandem mass spectra.

Intra-Specific Variation of Precocene I in the Wild Population of Ageratum conyzoides L. from the Western Himalayas

JPC – Journal of Planar Chromatography – Modern TLC -     

Visualization reagent for the identification of phthalates

JPC – Journal of Planar Chromatography – Modern TLC -     

The Potential of BioArena in the Study of the Formaldehydome

JPC – Journal of Planar Chromatography – Modern TLC - New results with BioArena as a complex separation and detection (evaluation) system support earlier observations that formaldehyde...     

The Absence of ß-Carotene and the Presence of Biliverdin in the Medicinal Leech Hirudo medicinalis as Determined by TLC

JPC – Journal of Planar Chromatography – Modern TLC -     

Syntheses of the Macrocyclic Spermine Alkaloids (±)‐Budmunchiamine A – C

The syntheses of four macrocyclic spermine alkaloids, (±)‐budmunchiamine A – C ( 1a – c ) and (±)‐budmunchiamine L4 ( 1 ), were accomplished by Michael addition of spermine to the α,β‐unsaturated esters 3a – d , followed by cyclization of the resulting α,ω‐tetraamino esters 4a – d with triethoxyantimony; N‐methylation of the amino lactams 6a – c yielded the budmunchiamines A – C ( 1a – c ).     

Determination of the Lipophilicity of Bioactive 2-Phenylbenzothiazoles by RPTLC

JPC – Journal of Planar Chromatography – Modern TLC -     

Determination of the Lipophilicity of Xanthines by Reversed-Phase Liquid Chromatography

JPC – Journal of Planar Chromatography – Modern TLC -     

Effect of trans-Resveratrol and Ascorbigens on the Fire Blight Pathogen Erwinia amylovora in the BioArena System

JPC – Journal of Planar Chromatography – Modern TLC - On the basis of our earlier observations, preliminary experiments were conducted with the fire blight pathogen Erwinia amylovora...     

Applicability of the BioArena System to Investigation of the Mechanisms of Biological Effects

JPC – Journal of Planar Chromatography – Modern TLC - Bioautography can be extended to a complex system called BioArena by linking different steps to it, for example dissolving a...     

Study of the Retention Behavior of Newly Synthesized s-Triazine Derivatives in RP TLC Systems,and the Lipophilicity of the Compounds

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of nine newly synthesized s-tri-azines has been studied by thin-layer chromatography on C18/UV254...     

A New Chromogenic Spray Reagent for the Detection and Identification of Monocrotophos

JPC – Journal of Planar Chromatography – Modern TLC -     

Different Chromatographic Methods for the Simultaneous Determination of Vitamin E and Vinpocetine in Their Combined Dosage Form and in the Presence of the Alkaline-Induced Degradation Product of Vinpocetine

JPC – Journal of Planar Chromatography – Modern TLC - Accurate, selective, and sensitive thin-layer chromatography (TLC)—densitometry and reversed-phase high-performance liquid...     

HPTLC Determination of Antioxidants in the Polymer Container of Parenteral Infusion Fluid

JPC – Journal of Planar Chromatography – Modern TLC -     

Influence of the Mobile-Phase Modifier on the Retention of Some para-Substituted Amides; Correlation with Compound Lipophilicity

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of para-substituted amides of α-phenylacetic, benzoic, propanoic, and 2,2-dimethylpropanoic acid...     

OPLC Investigation of the Effect of Cold-hardening on the Level of Polyamines in Wheat

JPC – Journal of Planar Chromatography – Modern TLC - The effect of cold-stress (2°C, 7 days cold-hardening) on the level of polyamines in different varieties of wheat and...     

Fluorescence Evaluation Using the Kubelka-Munk Formula

JPC – Journal of Planar Chromatography – Modern TLC - A new formula is presented for transforming fluorescence measurements in accordance with Kubelka-Munk theory. The fluorescence...