The phys.org articleSurprising chemical complexity of Saturn's rings changing planet's upper atmosphere about the chemical complexity of Saturn's rings, quotes a member of the INMS (Thomas Cravens) as saying,
What the paper is describing is the environment in the gap between the inner ring and upper atmosphere, and some of the things found were expected, such as water," Cravens said. "What was a surprise was the mass spectrometer saw methane—no one expected that. Also, it saw some carbon dioxide, which was unexpected. The rings were thought to be entirely water. But the innermost rings are fairly contaminated, as it turns out, with organic material caught up in ice. (italics and boldface are mine).
What is the nature of this organic material?
Does he simply mean a few carbon-based molecules like methane, propane, and butane, or maybe only methane, or is it a much more interesting cocktail of chemicals than that?
It also links to Chemical interactions between Saturn’s atmosphere and its rings published in Science, but the article is paywalled.