posted on 2022-07-13, 00:03authored bySebastian Wolf, Robert Domes, Andreas Merian, Christian Domes, Torsten Frosch
Raman spectroscopy provides an extremely high chemical
selectivity.
Raman difference spectroscopy is a technique to reveal even the smallest
differences that occur due to weak interactions between substances
and changes in the molecular structure. To enable parallelized and
highly sensitive Raman difference spectroscopy in a microtiter-array,
a diffractive optical element, a lens array, and a fiber bundle were
integrated into a Raman spectroscopy setup in a unique fashion. The
setup was evaluated with a microtiter-array containing pyridine–water
complexes, and subwavenumber changes below the spectrometer’s
resolution could be resolved. The spectral changes were emphasized
with two-dimensional correlation analysis. Density functional theory
calculation and “atoms in molecule” analysis were performed
to simulate the intermolecular long-range interactions between water
and pyridine molecules and to get insight into the involved noncovalent
interactions, respectively. It was found that by the addition of pyridine,
the energy portion of hydrogen bonds to the total complexation energy
between pyridine and water reduces. These results demonstrate the
unique abilities of the new setup to investigate subtle changes due
to biochemically important molecular interactions and opens new avenues
to perform drug binding assays and to monitor highly parallelized
chemical reactions.