One limitation in the growing field of ambient or direct analysis methods is reduced selectivity caused by the elimination of chromatographic separations prior to mass spectrometric analysis. We explored the use of high-field asymmetric waveform ion mobility spectrometry (FAIMS), an ambient pressure ion mobility technique, to separate the closely related opiate isomers of morphine, hydromorphon...

Ambient ionization mass spectrometric imaging of all parts of the seedling of Dysoxylum binectariferum Hook. f (Meliaceae) was performed to reconstruct the molecular distribution of rohitukine (Rh) and related compounds. The species accumulates Rh, a prominent chromone alkaloid, in its seeds, fruits, and stem bark. Rh possesses anti-inflammatory, anti-cancer, and immuno-modulatory properties. D...

Detecting a small molecular-weight compound by electrospray ionization mass spectrometry (ESI-MS) requires the compound to obtain a charge. Factors such as gas-phase proton affinities and analyte surface activity are correlated with a positive ESI-MS response, but unfortunately it is extremely challenging to predict from a chemical structure alone if a compound is likely to yield an observable ...

The breakthrough in soft ionization methods for biopolymers, electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) (1,2), revolutionized mass spectrometry (MS). As a result of these effective bioanalytical technologies, the entire field of proteomics changed, and the use of mass spectrometers for protein identification by accurate mass measurements or de novo seq...

A difference diffusion-based NMR technique and cold-spray ionization mass spectrometry were employed as a solution-based approach for identifying a ligand binding with a protein receptor. The difference diffusion-based NMR technique, called difference NOE-pumping, can directly detect the ligand interacting with a protein receptor. This technique uses a simple pulse sequence and the diffusion fi...

RATIONALE With the current state-of-the-art detection of ions only taking place under vacuum conditions, active pixel detectors that operate under ambient conditions are of particular interest. These detectors are ideally suited to study and characterize the charge distributions generated by ambient ionization sources. METHODS The direct imaging capabilities of the active pixel detector are u...

The first hyphenation of high performance liquid chromatography (HPLC), electrochemical online oxidation and mass spectrometry (MS) is described. Ferrocenecarboxylic acid esters of various alcohols and phenols have been synthesized, separated by reversed-phase HPLC and oxidized (ionized) coulometrically prior to single quadrupole MS analysis using electrospray ionization (ESI) and atmospheric p...

We present a novel probe design for ambient laser-based mass spectrometry imaging combining electrospray ionization (ESI) and atmospheric pressure chemical (APCI) in single probe, compatible with commercial laser ablation (LAESI) instrument. Here we describe the considerations features, as well an in-house developed data processing routine designed to extract accurate from post-ionization exper...

The synthesis and characterization of isotopomer tandem nucleic acid mass tag-peptide nucleic acid (TNT-PNA) conjugates is described along with their use as electrospray ionisation-cleavable (ESI-Cleavable) hybridization probes for the detection and quantification of target DNA sequences by electrospray ionisation tandem mass spectrometry (ESI-MS/MS). ESI-cleavable peptide TNT isotopomers were ...

The anthocyanins of the fruit skin of Iranian forest pear (Sange Khouj) were separated, identified and quantified using high-performance liquid chromatography/diode array detection (HPLC/DAD) and HPLC/electrospray ionization /mass spectrometry (HPLC/ESI /MS). The individual anthocyanins were identified by comparing their mass spectral data and retention times with those of standards and publish...