Direct analysis of camptothecin from Nothapodytes nimmoniana by desorption electrospray ionization mass spectrometry (DESI-MS)

Desorption electrospray ionization was employed for fast and direct ambient detection of the anti-tumor drug, camptothecin, and its derivative, 9-methoxycamptothecin in Nothapodytes nimmoniana. Different parts of the plant such as leaves, stems and bark were examined. The ion intensities suggest that the concentration in bark is higher than that in the leaves and stems. The method does not require any sample preparation or preseparation. The identity of the alkaloids was further confirmed by tandem mass spectrometry

Two 8C-methylated Flavonols from the Leaves of Vellozia candida Mikan (Velloziaceae)

From the leaves of Vellozia candida Mikan (Velloziaceae) the new flavonol 3',4',5,7-tetrahydroxy-3,6-dimethoxy-8-methylflavone and its known 7-O-methyl derivative, 3',4',5-trihydroxy-3,6,7-trimethoxy-8-methylflavone, were isolated and characterized by spectral data, including 2D NMR and tandem mass spectrometry experiments. The 5-hydroxy-3,3',4',6,7-pentamethoxy-8-methylflavone derivative was obtained by methylation with diazomethane

Reactive DESI-MS imaging of biological tissues with dicationic ion-pairing compounds

This work illustrates reactive desorption electrospray ionization mass spectrometry (DESI-MS) with a stable dication on biological tissues. Rat brain and zebra fish tissues were investigated with reactive DESI-MS in which the dictation forms a stable bond with biological tissue fatty acids and lipids. Tandem mass spectrometry (MS/MS) was used to characterize the dication (DC9) and to identify linked lipid-dication compounds formed. The fragment m/z 85 common to both DC9 fragmentation and DC9-lipid fragmentation was used to confirm that DC9 is indeed bonded with the lipids. Lipid signals in the range of m/z 250–350 and phosphoethanolamines (PE) m/z 700–800 observed in negative ion mode were also detected in positive ion mode with reactive DESI-MS with enhanced signal intensity. Reactive DESI-MS imaging in positive ion mode of rat brain and zebra fish tissues allowed enhanced detection of compounds commonly observed in the negative ion mode

Direct Plant Tissue Analysis and Imprint Imaging by Desorption Electrospray Ionization Mass Spectrometry

The ambient mass spectrometry technique, desorption electrospray ionization mass spectrometry (DESI-MS), is applied for the rapid identification and spatially resolved relative quantification of chlorophyll degradation products in complex senescent plant tissue matrixes. Polyfunctionalized nonfluorescent chlorophyll catabolites (NCCs), the “final” products of the chlorophyll degradation pathway, are detected directly from leaf tissues within seconds and structurally characterized by tandem mass spectrometry (MS/MS) and reactive-DESI experiments performed in situ. The sensitivity of DESI-MS analysis of these compounds from degreening leaves is enhanced by the introduction of an imprinting technique. Porous polytetrafluoroethylene (PTFE) is used as a substrate for imprinting the leaves, resulting in increased signal intensities compared with those obtained from direct leaf tissue analysis. This imprinting technique is used further to perform two-dimensional (2D) imaging mass spectrometry by DESI, producing well-resolved images of the spatial distribution of NCCs in senescent leaf tissues

Tissue imprint imaging by desorption electrospray ionization mass spectrometry

Cross-sections of Myristica malabarica (Lam) seed and mouse brain tissue were imprinted on such ordinary surfaces as printer paper and TLC plates, and successfully imaged by desorption electrospray ionization mass spectrometry (DESI-MS) at 250 µm resolution. Chemical images representing the distribution of the alkaloid malabaricone C in the seed substructures and individual lipids in the substructures of the brain were obtained. Practical implications include analysis of irregular or soft materials, easy recording, transportation and storage of the latent image, and posterior analysis of the samples by different techniques without the requirement of addition of matrices or use of specific types of surfaces