Rapid screening and characterization of metabolites from a marine-derived actinomycete by high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry.

A rapid and reliable method has been optimized and established for the analysis of the metabolites from a marine actinomycete by high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC/QTOF MS/MS). From MS/MS spectra, the product ions of [M + H](+) were recorded to provide abundant structural information of the mother nucleus and peptide moieties. Using the QTOF MS/MS and in-source collision-induced dissociation (in-source CID) techniques, three main metabolites including actinomycin D, actinomycin V and actinomycin I were determined and characterized by elemental compositions of precursor and product ions (<7 ppm).

[Indirect determination of Vc with flame atomic absorption spectrometry].

In the present paper, a new method for indirect determination of Vc by atomic absorption spectrometry is proposed, based on the reducing properties of Ag+. The effects of temperature, reaction time and use level of Ag+ on the experiment were studied. Room-temperature and reaction time of 35 minutes were chosen.