Supermolecule-assisted imaging of low-molecular-weight quaternary-ammonium compounds by MALDI-MS of their non-covalent complexes with cucurbit[7]uril.

Cucurbit[7]uril was used to form non-covalent complexes with low-molecular-weight quaternary-ammonium compounds for their indirect analysis by MALDI-MS. By shifting the ion signals to a higher and interference-free mass region, the distributions of neurine, choline, and phosphocholine in rat brain were visualized by MALDI imaging with high selectivity and good sensitivity.