Detection and sampling of dissolved hydrocarbons of interest in an environment expected to have hydrocarbon molecules, such as a water column or interstitial water in sediment. An apparatus comprising at least one oleophilic film frame is deployed into the environment and the at least one oleophilic film frame is exposed thereto for a defined period of time, and thereafter isolated from the environment to cease exposure thereto. Hydrocarbon molecules scavenged by the oleophilic film may be analyzed to determine their type and/or concentration.