A commercially available ion mobility spectrometer was interfaced to a custom-built linear time-of-flight (TOF) mass spectrometer for the purpose of examining electrospray-generated plumes. Ionic species that were separated in the ion mobility spectrometer could be selectively determined with the TOF mass spectrometer. Tetraalkylammonium salts, a peptide, and proteins were examined. Their ion m...

Mass analysis is demonstrated for the detection of sub-microgram quantities of explosive samples on a metallic surface at atmospheric pressure using laser electrospray mass spectrometry (LEMS). A non-resonant femtosecond duration laser pulse vaporizes native samples for subsequent electrospray ionization and transfer into a time-of-flight mass spectrometer. LEMS was used to detect 2,3-dimethyl-...

Image charge detection has been used to measure the charge and velocity of individual electrosprayed water droplets. With a positive bias on the electrospray needle the majority of the droplets are, as expected, positively charged. However, a small fraction, surprisingly, carry a negative charge. Plausible explanations for the presence of the negatively charged droplets are discussed. In partic...

Abstract Diabetes mellitus is becoming increasingly prevalent worldwide and needs effective clinical treatment methods. β-Cell replacement therapy has become a safe alternative for diabetes in recent years, encapsulation methods have been proposed to facilitate this type of therapy. Here, we used coaxial microfluidic electrospray technology generate microcapsules allowing high cell viability (&...

Abbreviations: PTMs=post-translational modifi cations; PPIs=protein-protein interactions; SDS-PAGE= sodium dodecyl sulfate-polyacrylamide gel electrophoresis; 2D-PAGE=two-dimensional polyacrylamide gel electrophoresis; MS=mass spectrometry; ESI=electrospray ionization; MALDI=Matrix Assisted Laser Desorption Ionization; ESI-MS=electrospray ionization mass spectrometry; MALDI-MS=MALDI mass spectr...

Mass analysis using laser electrospray mass spectrometry (LEMS) is demonstrated for the detection of trace samples of explosives at atmospheric pressure directly from a substrate. A non-resonant femtosecond duration laser pulse vaporizes native samples at atmospheric pressure for subsequent electrospray ionization and transfer into a mass spectrometer. LEMS was used to detect < 1 µg of 2,3-dime...

The high performance liquid chromatography-electrospray ionization-mass spectrometry method has been applied to the measurement of bile acid transport activities in membrane vesicles obtained from a human bile salt export pump expressing Sf9 cells. The amounts of bile acids transported using the human bile salt export pump expressing Sf9 cells were determined using liquid chromatography-electro...

A nonresonant femtosecond laser pulse, with an intensity of 10(13) Wcm(-2), vaporizes proteins and biomolecules intact, regardless of molecular structure, size or electronic structure for subsequent electrospray ionization and transfer into a mass spectrometer. Rapid, direct analysis from dried sample, aqueous solution and cellular material is demonstrated at atmospheric pressure using laser el...

We present the current status of the development of microfluidic devices fabricated on different substrates for coupling with electrospray ionization-mass spectrometry (ESI-MS). Until now, much success has been gained in fabricating the ESI chips, which show better performances due to miniaturization when compared with traditional methods. Integration of multiple steps for sample preparation an...

The structure of unknown compounds present in herbal products was elucidated using liquid chromatography-electrospray ionization-mass spectrometry, direct-infusion electrospray ionization-mass spectrometry, and nuclear magnetic resonance. Compounds 1-3 were identified as sildenafil analogues, 1 bearing an N-ethylpiperazine moiety instead of an N-methylpiperazine, and an acetyl group instead of ...