When a molecule is cryptochiral, it is particularly difficult to determine its stereochemistry. Using vibrational circular dichroism, a group from Groningen has managed to crack this tough problem, as they report in Chemistry A European Journal.

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are lipids that are mainly found in the membranes of archaea and acidobacteria. Geochemists use these lipids to determine the temperature of a sediment sample of a certain age. ‘It is difficult to make unambiguous measurements of these types of lipids because there is no good calibration worldwide’, says Adri Minnaard, professor of organic chemistry at the University of Groningen. ‘You need reference compounds, and these are not really available yet. We see this as an incentive to produce such substances.’