The dissolution of fluoranthene crystals

Fluoranthene is a polycyclic aromatic hydrocarbon (PAH) and belongs to a group of organic molecules detectable in the matrix of carbonaceous chondrites (CC). In CCs fluoranthene is suggested to play a role in reactions that contribute to the diversity of organic material. These reactions are assumed to take place in presence of water. Fluoranthene, however, is hardly soluble in water and not much is known about how it dissolves. We performed experiments where we in situ observed the surface of a fluoranthene crystal during interacting with different aqueous solutions, using an atomic force microscope (AFM). From these observations we can determine a dissolution rate of fluoranthene, when exposed to water, water with dissolved NaCl, water with dissolved MgSO4, and air. The observations indicate that fluoranthene crystals sublimate faster in air than they dissolve in pure water. We will discuss the implications for fluoranthene in carbonaceous chondrites.