Ionization and molecular weight (MW) determination of megadalton size plasmid DNA has been achieved using electrospray ionization (ESI) with Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. DNA molecules were shown to remain intact through electrospray ionization by collection on a specially prepared surface, followed by agarose gel electrophoresis. Individual highly charged...

Electrospray ionization (ESI) generates intact gas-phase ions from analytes in solution for mass spectrometric investigations. ESI can proceed via different mechanisms. Low molecular weight analytes follow the ion evaporation model (IEM), whereas the charged residue model (CRM) applies to large globular species. A chain ejection model (CEM) has been proposed for disordered polymers.

Intrinsically disordered proteins (IDPs) exert key biological functions but tend to escape identification and characterization due to their high structural dynamics and heterogeneity. The possibility to dissect conformational ensembles by electrospray-ionization mass spectrometry (ESI-MS) offers an attracting possibility to develop a signature for this class of proteins based on their peculiar ...

Dissociation of disulfide is normally mandatory prior to disulfide peptide sequencing via electrospray ionization collision induced dissociation mass spectrometry (ESI-CID-MS). Herein, a facile method for directly sequencing intact disulfide peptides was proposed. The basic principles involved were electrolyte-enhanced corona discharge in ESI and the following oxidative cleavage reaction.

Mass spectrometry (MS) owes its remarkable rise as a bioanalytical tool to the development of two “soft” ionization techniques: matrix-assisted laser desorption/ ionization (MALDI) (1,2) and electrospray ionization (ESI) (3). The salient feature of soft ionization is that a wide range of analytes, from small metabolites to very large biomolecular systems, can be transferred intact into the gas ...

the chemical components in the decoctions of chinese herbal medicines are not always the same as those in the crude herbs because of the insolubility or instability of some compounds. in this work, a high-performance liquid chromatography (hplc) coupled with electrospray ionization (esi) tandem mass spectrometry method was developed to explore dynamic variation patterns of aconitum alkaloids in...

This review addresses the determination of the internal energy of ions produced by electrospray ionization (ESI) sources, and the influence of the internal energy on analyte fragmentation. A control of the analyte internal energy is crucial for several applications of electrospray mass spectrometry, like structural studies, construction of reproducible and exportable spectral libraries, analysi...

Liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) has been frequently utilized for the sensitive and selective determination of the trace level compounds in biological samples. In LC/ESI-MS/MS, chemical derivatization is sometimes used to enhance the detection sensitivity of the analytes. This review presents an overview of the derivatization rea...

The approach of two different ionization techniques including electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was tested for the analysis of cholesteryl esters (CEs). The retention time (RT), signal intensity, protonated ion, and product ion of CEs were compared between ESI and APCI. RT of C...

glucagon like peptide-1; Ala: Alanine; Gly: Glycine; Pro: Proline; HTS: high-throughput screening; ESI: electrospray ionization; APCI: Atmospheric Pressure Chemical Ionization; pNA: p-nitroanilide; Asp: Aspartic acid; Thr: Threonine; Met: Methionine; Phe: Phenylalanine; Leu: Leucine; Ser: Serine; HOBT: Hydroxybenzotriazole ; EDCI: 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride; Me:...