A systematic approach was used to evaluate the electrospray ionization mass spectral (ESI-MS) analysis of sucrose octasulfate (SOS), an important pharmaceutical agent. SOS represents a model for other suffated carbohydrates, such as heparin and glycosaminoglycan-derived oligosaccharides that also are highly sulfated and pose difficult analytical problems. A survey of ammonium counterions showed...

The purpose of the work presented here was to evaluate the influence of solution composition and analyte characteristics on responsiveness to analysis with negative ion electrospray ionization mass spectrometry. The responses of a series of structurally diverse acidic molecules were compared in various solvents. Response was generally observed to be higher in methanol than acetonitrile and resp...

A colloidal graphite-coated emitter is introduced for sheathless capillary electrophoresis/nanoelectrospray ionization time-of-flight mass spectrometry (CE/ESI-TOFMS). The conductive coating can be produced by brushing the capillary tip to construct a fine layer of 2-propanol-based colloidal graphite. The fabrication involves a single step and requires less than 2 min. Full cure properties deve...

Some compounds readily form [M+46]+ adduct ions during positive ion electrospray ionization mass spectrometry ((+)ESI-MS) analysis. These [M+46]+ ions were characterized as [M+CH3CH2NH2+H]+ by accurate mass determination. Ethylamine involved in the adduct was proposed to be the reduction product of acetonitrile and this was confirmed using deuterated acetonitrile. Other nitrile-containing compo...

A simple and sensitive high performance liquid chromatography-electrospray ionization mass spectrometry method has been evaluated for the assignment of clonidine hydrochloride in human plasma. The mobile phase composed of acetonitrile–water 60:40 (v/v), and 0.2% formic acid 20 µL of sample was chromatographically analyzed using a repacked ZORBAX-XDB-ODS C18 column (2.1 mm×30 m...

This paper is a part of study on reactivity descriptors in vacuum gas oil hydrotreatment (VGO HDT). It aims to understand the differences feeds various process origins and corresponding hydrotreated effluents molecular level. Four different oils were over sulfided NiMo/Al2O3 catalyst at wide range temperatures residence times order collect HDT broad hydrodenitrogenation (HDN) conversions. Vacuu...

A novel prenylflavonol glycoside, named acetylicariin, has been isolated from the aerial parts of Epimedium koreanum Nakai. The structure has been identified by electrospray ionization multi-stage tandem mass spectrometry (ESI-MSn) and other chemical evidence, which has been elucidated as 8-prenylkaempferol-4'-methoxyl-3-O-alpha-L-rhamnopyranosyl-7-O-beta-D-(2"-O-acetyl)glucopyranoside.

A HPLC-ESI-IT-MSn method, based on high-performance liquid chromatography coupled to electrospray negative ionization multistage ion trap mass spectrometry, was developed for rapid identification of 24 flavonoid and naphthopyranone compounds. The methanol extracts of the capitulae and scapes of P. chiquitensis exhibited mutagenic activity in the Salmonella/microsome assay, against strain TA97a.

Dimeric tetraalkyldistannoxanes are have been reported to catalyze esterification reactions, but are difficult to investigate in detail due to the lack of suitable spectroscopic handles. Electrospray ionization mass spectrometry (ESI-MS), in conjunction with a tethered charge on a tin atom, reveals that immediate decomposition to mono-tin carboxylate compounds occurs in the presence of carboxyl...

The HPLC system was equipped with a Waters XBridgeTM C18 column (2.1 × 150 mm, 5 μm), and the column temperature was set to 25 °C. The mobile phases for metabolic fingerprinting consisted of 0.1% formic acid in Milli-Q water and 5 mM ammonium acetate in Milli-Q water (solvent A, positive electrospray ionization (ESI+) and negative electrospray ionization (ESI–), respectively), acetonitrile (sol...