Robert D. Minard

Chemistry in Ancient and Modern Environments

Dr. Minard's research involves the application of mass spectrometry, NMR, and other instrumental methods to structural investigations of complex materials of evolutionary, environmental, or biochemical importance. One challenging area of current work attempts to answer the age-old questions "Where did we (life) come from?" and "Is there life beyond this earth?" Astronomers have shown that hydrogen cyanide (HCN) is present in interstellar clouds, comets, and the atmospheres of some planets and moons in our solar system. In experiments simulating the atmospheric/oceanic chemistry postulated to have occurred on the early earth, chemists have detected both HCN and polymeric HCN, an orange to black solid readily formed from HCN in both gas and liquid phases. Spectral and chemical degradation studies have shown that this solid has a very complex heterogeneous structure that varies with the conditions of its formation. Application of a new and powerful degradative technique developed at Penn State has revealed the remarkable nature of this material. By heating the polymer with tetramethylammonium hydroxide at 250-300oC (TMAH thermochemolysis), concommitant bond cleavage and in situ methylation take place yielding a large number of products that can be separated and analyzed by GC-MS (Figure 1). This reveals that HCN polymer has structural subunits of many types: diacyl, amino acyl, purine/pyrimidine, or triazine structural motifs relevant to biochemistry.

TMAH thermochemolysis is being used to study other complex macromolecular materials from simulation experiments and carbonaceous meteorites such as the Murchison. For example, when applied to the solid organic residues (named tholins by Carl Sagan and coworkers) formed in experiments simulating the chemistry occurring in the brown hazy atmosphere of Saturn's largest moon Titan, many of the products are the same as those derived from HCN polymer. Thus, HCN polymer chemistry is very likely taking place right now in our solar system. The Cassini-Huygens space probe will arrive at Titan in 2003 and hopefully corroborate the simulation results. This same HCN chemistry probably took place on the primitive earth.

Our initial results indicate that HCN polymers have macromolecular heterogeneity capable of molecular recognition (catalysis and base pairing) and information storage. If this can be proven, they may represent the first stage in the chemical evolution of a true biopolymer.

Dr. Minard's interest in environmental chemistry has recently turned to the study of trace and ultratrace nutrients in aquatic ecosystems using freshwater and saltwater aquariums in the new HUB-Robeson aquarium at Penn State. Specifically, work on the coral reef buffering and organic matter binding of trace nutrients will be examined.

Dr. Minard also devotes considerable time and energy to the development of new approaches to organic laboratory instruction including creation of multimedia software to guide students through the operation of complex instrumentation such as NMR and GC.