Identification of polyoxypregnane glycosides from the stems of Marsdenia tenacissima by high-performance liquid chromatography/tandem mass spectrometry.

A facile method based on high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC/(+)ESI-MS(n)) has been established for the analysis of polyoxypregnane glycosides in the stems of Marsdenia tenacissima. The data reveals the ability of MS(n) in the structural elucidation of polyoxypregnane glycosides including the nature of the polyoxypregnane core, the kinds of the substituents and the types of sugar residues. Offline Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) is also performed to assign accurate elemental compositions.

Frequency scan for the analysis of high mass ions generated by matrix-assisted laser desorption/ionization in a paul trap.

An ion trap has been modified for the analysis of high mass ions generated by matrix-assisted laser desorption/ionization. Samples are deposited on a probe tip and introduced directly onto the hyperbolically shaped surface of one endcap. All three electrodes - both the endcaps and the ring electrode - are insulated so that the radio frequency (Rf) voltage may be applied to the center ring electrode and the inverted Rf voltage to the endcaps.

Studies on the selection of new matrices for ultraviolet matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

A new group of compounds has been successfully tested as matrices for ultraviolet matrix-assisted laser desorption/ionization mass spectrometry (UV-MALDI MS). Several new matrices for UV-MALDI MS have been found by choosing, as potential matrices, compounds that perform an intramolecular proton transfer along an intramolecular H-bond under UV irradiation. Compounds of this type are, for example, salicylamide, salicylanilide, several ortho-hydroxyacetophenones and ortho-hydroxybenzophenones.

Sequestration ofVeratrum alkaloids by specialistRhadinoceraea nodicornis konow (Hymenoptera, Tenthredinidae) and its ecoethological implications.

The larvae of the specialist sawflyRhadinoceraea nodicornis Konow (Hymenoptera, Tenthredinidae) store in their hemolymph ceveratrum alkaloids originating from the host plantVeratrum album L. (Liliales, Melanthiaceae). The major alkaloid found in the hemolymph is 3-acetyl-zygadenine.

Incorporation of atmospheric NO-nitrogen into free amino acids by Norway spruce Picea abies (L.) Karst.

During spring and autumn 1991, potted 6-yearold spruce trees (Picea abies (L.) Karst.) were fumigated with 60 nl·1NO for 4 days under controlled conditions in constant light.