Professor of Chemistry
Associate Chair for Graduate Education
Ph.D. Iowa State University, 1986
The Synovec group is working in the areas of traditional analytical chemistry and bioanalytical chemistry, centered upon fundamental studies and applications of separation science. Primarily, the group works in the areas of gas chromatography (GC) and liquid chromatography (LC) instrumentation, sensors, analytical methodology, chemical measurement science and multivariate data analysis (chemometrics). Overall, the research group seeks to find a better fundamental understanding of the right balance of chemical separation and mathematical separation required to optimally glean the desired chemical information from analytical separation data. We complement our interest in developing and applying novel instrumentation and chemometrics software with a deep interest in modeling the chromatographic separation processes based upon theory. Our theoretical modeling has provided fundamental insight and guidance for instrumentation design improvements. Application of our separations technology in many exciting areas such as metabolomics, forensics, petroleum-based fuels, biofuels, and environmental systems are being explored.
In the area of GC, the fields of two-dimensional GC and chemometric data analysis are being integrated. Comprehensive two-dimensional GC instrumentation with time-of flight mass spectrometry detection (GC×GC-TOFMS) has been developed, improved upon, and applied, using two different modulation interfaces: valve-based and thermal-based. The GC×GC-TOFMS instrument provides an information-rich chemical fingerprint for complex samples, and the data is ideally suited for chemometric data analysis. Chemometrics plays a pivotal role in the analytical workflow for the translation of the raw data into useful information. We are exploring and developing advanced approaches for non-targeted discovery-based analysis of cross-sample comparisons of GC×GC–TOFMS data, coupled with robust deconvolution, identification and quantification of meaningful analytes. Specifically, we have been developing Fisher-ratio (F-ratio) analysis, a statistically-based data mining technique to discover analytes that distinguish sample classes based upon the experimental design. A recently developed tile-based F-ratio algorithm substantially improves chemical selectivity in the discovery process for the determination of an analyte “hit list.” In turn, important features discovered by the F-ratio analysis, the “hits”, are further analyzed using complementary chemometric methods. For this purpose, parallel factor analysis (PARAFAC) has been shown to confidently analyze GC×GC–TOFMS data for many studies, readily providing analyte deconvolution, identification, and quantification. For example, we are pioneering the development and implementation of the F-ratio software to find up- and down-regulated biomarker metabolites in metabolomics studies. Additionally, we are involved with forensic studies, where the goal is to find small concentration changes in chemical marker compounds that have significant forensic value. For many of the projects, we also develop and apply novel LC-MS/MS methods to provide a broader understanding of the chemical systems being investigated. For example, in metabolomics studies the metabolites determined by the GC and LC platforms are complementary, with some metabolites determined by both platforms, but many metabolites more readily determined by one approach than the other.
The group has also developed comprehensive three-dimensional gas chromatography instrumentation (GC×GC×GC), which provides interesting opportunities to study selectivity advantages of three separation dimensions working in concert. The GC×GC×GC research has been extended to include detection with TOFMS, producing a fourth order analytical instrument, opening up new opportunities for chemometric analysis of complex data sets. Concurrently, work in the area of ultra-high speed GC has been pioneered, with separations on the time scale of a chemical sensor (e.g., separations in the range of 50 ms to 500 ms). These ultra-high speed GC separations are opening up new opportunities in developing faster, more informative multi-dimensional GC instrumentation.
“Targeted Analyte Deconvolution and Identification by Four-Way Parallel Factor Analysis Using Three-Dimensional Gas Chromatography with Mass Spectrometry Data,” N. E. Watson and R. E. Synovec, Anal. Chim. Acta, 2017, 983, 67-75.
“Using Receiver Operating Characteristic Curves to Optimize Discovery-Based Software with Comprehensive Two-Dimensional Gas Chromatography with Time-of-Flight Mass Spectrometry,” B. C. Reaser, B. W. Wright and R. E. Synovec, Anal. Chem., 2017, 89, 3606-3612.
“Comprehensive Three-Dimensional Gas Chromatography with Time-of-Flight Mass Spectrometry,” N. E. Watson, H. D. Bahaghighat, K. Cui and R. E. Synovec, Anal. Chem., 2017, 89, 1793-1800.
“Method to Determine the True Modulation Ratio for GC × GC,” D. K. Pinkerton, B. A. Parsons and R. E. Synovec, J. Chromatogr. A, 2016, 1476, 114-123.
“Performance Evaluation of Tile-based Fisher Ratio Analysis using a Benchmark Yeast Metabolome Dataset,” N. E. Watson, B. A. Parsons and R. E. Synovec, J. Chromatogr. A, 2016, 1459, 101-111.
“Chemical Characterization of the Acid Alteration of Diesel Fuel: Non-Targeted Analysis by GC × GC–TOFMS with Tile-Based Fisher Ratio and Combinatorial Threshold Determination,” B. A. Parsons, D. K. Pinkerton, B. W. Wright and R. E. Synovec, J. Chromatogr. A, 2016, 1440, 179-190.