A MASSive laboratory tour. An interactive mass spectrometry outreach activity for children.

It is imperative to fascinate young children at an early stage in their education for the analytical sciences. The exposure of the public to mass spectrometry presently increases rapidly through the common media. Outreach activities can take advantage of this exposure and employ mass spectrometry as an exquisite example of an analytical science in which children can be fascinated.

An external matrix-assisted laser desorption ionization source for flexible FT-ICR Mass spectrometry imaging with internal calibration on adjacent samples.

We describe the construction and application of a new MALDI source for FT-ICR mass spectrometry imaging. The source includes a translational X-Y positioning stage with a 10×10 cm range of motion for analysis of large sample areas, a quadrupole for mass selection, and an external octopole ion trap with electrodes for the application of an axial potential gradient for controlled ion ejection. An off-line LC MALDI MS/MS run demonstrates the utility of the new source for data- and position-dependent experiments.

Protein identification with Liquid Chromatography and Matrix Enhanced Secondary Ion Mass Spectrometry (LC-ME-SIMS).

Secondary Ion Mass Spectrometry (SIMS) is a well established method for sensitive surface atomic and molecular analysis. Protein analysis with conventional SIMS has been attempted numerous times; however it delivers exclusively fragment peaks assigned to α-amino acids or immonium ions. In this paper we report experiments where direct sequence information could be measured thanks to a combination of HPLC separation with matrix enhanced SIMS (ME-SIMS) on tryptic digests of intact proteins.

MALDI-TOF mass spectrometry on cellulosic surfaces of fresh and photo-aged di- and triterpenoid varnish resins.

Matrix-Assisted Laser Desorption/Ionization Time-of-Flight mass spectrometry (MALDI-TOF-MS) on cellulosic surfaces is shown to be a suitable method for examining highly oxidized terpenoids, which are otherwise too difficult to determine by other techniques. By crystallization of a 2,5-dihydroxybenzoic acid (DHB) matrix and the sample solution on cellulose-coated thin layer chromatography(TLC) plates, spectra with good signal/noise ratios are obtained and no significant interferences due to matrix ions or cluster ions were produced, at least not in the range of m/z values of interest (>300 Da). The validity of the method was tested on natural di- and triterpenoid resins used as paint varnishes by Old Masters.

Does double electron capture lead to the formation of biradicals? An ECD-SORI-CID study on lacticin 481.

We studied lacticin 481, a small lantibiotic with three lanthionine bridges, by electron capture dissociation (ECD) in a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. Following electron capture, very little fragmentation was observed, but species formed by nondissociative single and multiple electron capture were abundant. Ions formed by double electron capture were subjected to sustained off resonance irradiation collision induced dissociation (SORI-CID) to determine whether stable biradicals were formed.

Localization of intramolecular monosulfide bridges in lantibiotics determined with electron capture induced dissociation.

Electron capture induced dissociation (ECD) and collisionally activated dissociation (CAD) experiments were performed on four lanthionine bridge-containing antibiotics. ECD of lantibiotics produced mainly c and z* ions, as has been observed previously with other peptides, but more interestingly, the less common c* and z ions were observed in abundance in the ECD spectra. These fragments specifically resulted from the cleavage of both a backbone amine bond and the thioether bond in a lanthionine bridge.

Effect of local matrix crystal variations in matrix-assisted ionization techniques for mass spectrometry.

Intense intact molecular ion signals have been obtained from phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidyiinositol using matrix-enhanced secondary ion mass spectrometry (ME-SIMS). It was found that the high-mass (m/z >500) regions of the ME-SIMS spectra closely resembled those obtained using matrix-assisted laser desorption/ionization (MALDI). Using high spatial resolution SIMS, a detailed investigation of dried-droplet samples was performed.

Manipulating internal energy of protonated biomolecules in electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.

The internal energy of protonated leucine enkephalin has been manipulated in electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry with two newly designed pump-probe experiments. Blackbody infrared radiation was applied to pump an ion population into a well-defined internal energy distribution below the dissociation threshold. Following this pumping stage, the internal energy distribution was probed using on-resonance collisional activation to dissociate the ions.

Electron capture and collisionally activated dissociation mass spectrometry of doubly charged hyperbranched polyesteramides.

Electron capture dissociation (ECD) of doubly protonated hyperbranched polyesteramide oligomers (1100-1900 Da) was examined and compared with the structural information obtained by low energy collisionally activated dissociation (CAD). Both the ester and amide bonds of the protonated species were cleaved easily upon ECD with the formation of odd electron (OE(.+)) or even electron (EE(+)) fragment ions.

Isomer separation of hyperbranched polyesteramides with gas-phase H/D exchange and a novel MS(n) approach: DoDIP.

Two approaches are introduced that provide information about the isomeric composition of hyperbranched polyesteramides. The first approach is based on a novel tandem mass spectrometric (MS(n)) approach that allows the study of different types of isomeric structures by a separation based on their difference in appearance energy. The method is called DoDIP: dissociation of depleted ion populations.