The Brodbelt research program involves the development of quadrupole ion trap mass spectrometry for a variety of interdisciplinary applications related to bioanalytical, organic, and inorganic areas.  Research efforts are currently focused in three areas:  A) evaluation of aspects of molecular recognition by development of new mass spectrometric methods,  B) development of photodissociation methods for the structural characterization of peptides, proteins, and DNA, and  C) the application of extraction, separation and mass spectrometric strategies for the identification and quantification of phytochemicals in food, urine and plasma for studies of biotransformation and bioavailability.

A) Molecular recognition
The phenomenon of molecular recognition is important in many biological and chemical systems, such as those responsible for drug actions, enzyme catalysis, and ion transport.  Advances in the field of molecular recognition have stimulated a growing need for new analytical methods for characterization of the structures of host-guest complexes and determination of binding selectivities.  One method which has shown great promise for the analysis of supramolecular assemblies and more complex quantitative applications is electrospray ionization-mass spectrometry (ESI-MS).  In the ESI method, complexes formed in solution are sprayed into the gas phase, and the types of complexes and distribution of complexes are analyzed.  This method has been used to study the binding properties of lariat ethers, calixarenes, molecular clefts, crown ethers, and a variety of other novel macrocycles.  In recent years, we have been examining DNA interactive agents to identify the binding sites and stoichiometries of drug/DNA complexes and to measure the sequence and drug selectivity.

B) Infrared Multiphoton Dissociation for Analysis of Biological Molecules
Infrared multiphoton dissociation is being developed to characterize the structures of biological molecules, with special emphasis on peptides, identification of peptide modifications, and sequencing of DNA. Infrared photodissociation has proven to be a universal way to energize ions so that they dissociate via structurally-informative pathways, and ways to make this method more energy-tunable are under development.

C) Analysis of Phytochemicals in Food, Urine and Plasma
Phytochemicals, such as flavonoids, limonoids, and anthocyanins, are chemopreventive compounds found naturally in plants that exert positive health effects as dietary antioxidants. Recent epidemiological and clinical studies have provided strong evidence that phytochemicals offer protection against cancer, heart disease, and aging-related problems.  Citrus fruit, kale, onions, berries, tea and soy are some of the best natural sources of flavonoids. Our goal is the development of electrospray ionization/quadrupole ion trap mass spectrometry for the sensitive detection of phytochemicals in foods like citrus and kale, and in plasma and urine after consumption, thus allowing the metabolism, uptake, distribution, and bioavailability of these compounds to be mapped. Electrospray ionization, in conjunction with tandem ion trap mass spectrometry and photodissociation methods, are being developed to characterize the structures of complex molecules, to detect trace quantities and metabolites in biological fluids, and to distinguish isomers.  The use of metal complexation is being explored as an alternative to conventional protonation as a means to efficiently generate ions.