We have a number of projects involving instrument development. Some of these projects are major such as building a new ion trap or developing a new ionization technique. Other projects are smaller involving modifications to current instruments to allow new experiments to be performed.

Some of the current projects are: design and construction of an ion trap that allows higher order components to the rf electric field to controlled electronically; development of electrospray/glow discharge ionization; modifications of an ion trap to perform infrared multiphoton photodissociation; development of atmospheric pressure matrix-assisted laser desorption/ionization; and development methods to analyze multiple ions simultaneously.

Our major focus to date has been the analysis of peptides. Mass spectrometry has been used for over a decade to sequence peptides and is now probably the method of choice. However, even the best computer algorithms do not have a high success rate in taking data and producing the correct peptide sequence because of the complexity of the gas phase chemistry.

Our effort related to peptide sequencing is in two related categories: understanding the gas phase chemistry and controlling the gas phase chemistry. In this regard we are using two unique capabilities of ion trapping instruments: the ability to do perform multiple stages of MS/MS (MSⁿ) and the ability to perform controlled ion/molecule reactions. We often complement our experimental data with theoretical calculations (semi-empirical or molecular dynamics) to determine if the structures we propose as the driving force behind the gas phase chemistry are reasonable from an energetic point of view.

The Chemistry Department at UNC has a very strong program in materials chemistry with a number of groups synthesizing very interesting polymers. We have evolved an interest in how to characterize these systems using mass spectrometry. Matrix-assisted laser desorption ionization (MALDI) is typically the ionization method of choice if analyzing polymers. However, this approach has some significant limitations and we feel that electrospray ionization (ESI) offers an attractive alternative.

The major problem with ESI is that is produces a charge state distribution for the oligomers that, when convoluted with the natural MW distribution generates very complex and often uninterpretable mass spectra. Again using unique capabilities of ion trapping instruments we have developed a means to chemically deconvolute the charge state distribution. This allows us to use ESI and take advantage of the coulombic destabilization of multiply charged ions to obtain MS/MS data on large oligomers.