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Using groundbreaking technology to uncover the truth about soil

 

André Simpson, Professor of chemistry at the University of Toronto Scarborough (UTSC), is a rare breed. Not only is he blazing a trail in the environmental sciences, he is also internationally renowned for the development of breakthrough technologies that are revolutionizing chemical analysis in general.

“My work centres on the development of nuclear magnetic resonance (NMR) spectroscopy for use in environmental research,” explains Simpson.

Recently honoured with the 2010 Principal’s Research Award for his outstanding contributions to the research profile and academic environment of UTSC, Simpson has been a pioneer in the use of NMR technology to begin unravelling the molecular-level mechanisms underpinning large-scale processes such as environmental contamination, global warming and agriculture.

“NMR is, bar none, the most powerful analytical tool we have in science,” says Simpson.

Capable of progressively zooming in from the visible scale to the atomic level, NMR spectroscopy provides information about the structure, interactions and reactivity of molecules in whole heterogeneous samples not accessible by any other analytical technique. It shows in three-dimensional space what atoms the molecules contain, how far apart those atoms are, what they are bonded to, how they react under specific conditions, and the extent of the interaction between the molecules themselves.

Illustrating the significance of this work by way of one of his research interests, namely the transport and fate of environmental contaminants, Simpson says: “There are many groups that measure levels of pollutants on a global scale, and follow the flow of those pollutants to determine their point source of origin. But there are very few that do what we do, which is to try to answer the how and why of that.

“In large part this is because, at the molecular-level, these questions become so incredibly complex. For example, organics dissolved in the ocean have been described as ‘the most complex mixture known to man’. As such the development of novel analytical tools is required to understand not just what these chemicals are but how they react with each other and the world around them.”

Digging deep

Simpson’s initial purpose in exploiting the analytical potential of NMR was to answer one question: What is soil? After 15 years of research, his findings overturned an understanding of the chemical structure of soil that had held sway since 1786.

“It was long thought that 80 per cent of soil was composed of humic substances, massive macromolecules that accumulated in the soil as plant materials and other substances degraded,” Simpson explains. Moreover, these humic substances were thought to be highly resistant to breakdown by environmental processes, that is, non-reactive.

By analyzing soil with the level of resolution available through NMR spectroscopy, Simpson was able to prove definitively that what had previously been understood as humic macromolecules, was in fact a very complex mixture of microbial and plant materials and the biomolecules they release as they degrade (peptides, sugars, nucleic acid residues, carbohydrates, fats, etc.) – a mixture which can be highly reactive.

This revolutionary concept of the structure of soil has huge implications for our understanding of trends in global warming.

“There is three times more carbon stored in soil than in all life on earth,” says Simpson.

In the traditional view, this carbon was locked up in these humic molecules, so no one expected it to react to warming, or possibly feedback on the carbon levels already in the atmosphere.

“But now that we know what soil is,” he continues, “we can more accurately model and predict what role it will play in climate change.”

Simpson’s research also lays the groundwork for the design of “ideal” pesticides (at present in many cases, 90 per cent of pesticides bind to soil and never reach the plant) and optimized soil remediation strategies.

“If we know, at the molecular level, what the binding sites in pesticides or contaminants are, we can design chemicals that eliminate or break those bonds,” he explains. “This could, in some cases, result in the application of 10 times less chemical to the soil, a win-win situation for farmers and the environment.”

Significant impact

The importance of his work is recognized not only by his colleagues, but also by industry. In 2004, Simpson founded UTSC’s Environmental NMR Centre, which he co-directs along with Myrna Simpson, Professor of environmental chemistry. The first centre in the world dedicated specifically to the development of NMR-based approaches for studying whole samples, it now houses approximately $5 million in state-of-the-art NMR instrumentation, approximately half of which was donated by Simpson’s long-time industry partner, Bruker BioSpin.

“Bruker is the global leader in NMR technology,” says Professor Malcolm Campbell, Vice-Principal of Research. “They very rightly view André as a leader in this field as well, and consequently place the very best instruments in his lab.”

Grants from the Canada Foundation for Innovation and the Natural Sciences and Engineering Research Council of Canada make up most of the remaining $2.5 million in funding.

Continuing to build on the methods and technologies he has pioneered, Simpson “is now set to transform chemical analysis in general by developing next-generation NMR,” heralds Campbell. Capable of following, with complete molecular resolution, the precise mechanisms taking place within any whole sample moving from a solution to a gel to a solid phase, Simpson’s latest innovations will be central to understanding the processes involved in the development of, for example, Parkinson’s, Huntington’s and heart disease, and even of terrestrial life itself.

“André is one of the giants upon whose shoulders others will stand,” predicts Campbell. “He is providing the platform that will give others the capacity to do more than they could ever have done previously.”




© University of Toronto Scarborough