High-performance liquid chromatography coupled to atmospheric pressure ionization-electrospray ionization mass spectrometry (API-ESI-MS) was investigated for the analysis of corticosterone metabolites; their characterization was obtained by combining the separation on Zorbax Eclipse XDB C18 column (eluted with a methanol-water-acetic acid gradient) with identification using positive ion mode AP...

A high-performance liquid chromatography-atmospheric pressure ionization-electrospray ionization mass spectrometry (HPLC-API-ESI-MS) method was developed for the analysis of steroids in a study of steroid-converting enzymes. Separations ware done on a Zorbax Eclipse XDB-C18 column (eluted with a linear methanol-water-acetic acid gradient) and identification of the steroids involved was done by ...

PCR coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) was compared with culture for pathogen detection in peritoneal dialysis (PD)-related peritonitis. Of 21 samples of PD effluent, PCR/ESI-MS identified microorganisms in 18 (86%) samples, including Mycobacterium tuberculosis in 1 culture-negative sample. Of 15 double-positive samples, PCR/ESI-MS and culture reached levels of ...

Electrospray ionization (ESI) coupled with high-resolution mass spectrometry (HRMS) is rapidly developing into a powerful tool for the molecular characterization of petroleum fractions. However, occurrence ion–molecule aggregates seriously affects interpretation results. Ion–molecule are not inherent compounds in but they produced during analysis samples by spectrometry. Also, classes same as m...

We demonstrated the complementary use of inductively coupled plasma-mass spectrometry (ICP-MS) and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) for the analysis of Se-containing compounds, such as selenate, selenomethionine (SeMet), and trimethylselenonium ion (TMSe), found in biological samples. The sensitivity of ESI-Q-TOF-MS for Se-containing compounds w...

The lack of authentic standards has limited the quantitative analysis of herbal drugs in biological samples. The present work demonstrated a practicable strategy for the assay of herbs and their metabolites independent of authentic standards. A liquid chromatography–electrospray ionization–mass spectrometry (LC–ESI–MS) method for the qualitative and quantitative determination of the metabolites...

The unsymmetrical Mn-Anderson polyoxometalate cluster, [N(C4H9)4]3[MnMo6O18(C4H6O3NO2)(C4H6O3NH2)] (1; N(C4H9)4(+) = TBA(+)), has been prepared and characterized by X-ray crystallography and electrospray ionization mass spectrometry (ESI-MS). Covalent functionalization of compound 1 leads to the controlled assemblies of unsymmetrical alkoxopolyoxometalate clusters of compounds 2-5, which can be...

A rapid method for the characterization of sake by measuring the ratio of the peak intensities of taste components in sake, using electrospray ionization/mass spectrometry (ESI/MS) has been developed. Twenty-six different kinds of sake samples were collected and analyzed by ESI/MS. The ESI/MS ion peaks were assigned to amino acids, organic acids, and sugars. Principal component analysis was per...

The final stages of electrospray ionization (ESI) of four different proteins were simulated with molecular dynamics and the resulting trajectories analyzed with respect to structure preservation, evaporation and the protecting effect of hydrating water layers. For all proteins except insulin the structure was well preserved in the presence of a hydrating water layer. The results provide new ins...

Molecular weight distributions of fulvic acid from the Suwannee River, Georgia, were investigated by electrospray ionization/quadrupole mass spectrometry (ESI/ QMS), and fragmentation pathways of specific fulvic acid masses were investigated by electrospray ionization/ion trap multistage tandem mass spectrometry (ESI/MST/ MS). ESI/QMS studies of the free acid form of low molecular weight poly(c...