Harvard physicists have developed a novel technique that can detect molecular variants in chemical mixtures greatly simplifying a process that is one of the most important, though time-consuming, processes in analytical chemistry.
As described in a paper in Nature, post-doctoral researcher David Patterson, Professor of Physics John Doyle and Dr. Melanie Schnell of the Center for Free-Electron Laser Science (CFEL) in Hamburg, Germany developed a system that relies on finely-tuned microwave fields to identify molecular variants apart, and to determine how much variant is in a mixture.
The ability to tell such variants apart, researchers said, is critical because many chemical compounds exist in two forms, each of which is a mirror image of the other. Such molecules are called chiral, from the ancient Greek for hand, and are often described as being either "right-handed" or "left-handed."
Knowing whether a molecule is right- or left-handed, scientists say, is important, because each type of molecule behaves differently in chemical reactions. Much of biology, for example, is predicated on the idea that amino acids are "left-handed," while sugar molecules are "right-handed."
"The 'wrong' sort of a compound can function completely differently in an organism," explains Schnell, who leads an independent Max Planck research group for structure and dynamics of molecules at CFEL. "In the best case it is just ineffective. In the worst case it is toxic."
The challenge, however, is that telling the two variants of a chiral molecule apart is no easy job.
A common way to discern between them is to shine linear polarised light through them. While one variant will turn the plane of polarisation to the left, the other will turn it to the right. The problem with that method, researchers say, is that it produces rather weak effects, and can only be used on liquid samples, and it can be difficult to use on samples th
|Contact: Peter Reuell|