Abstract: In a principal embodiment, the invention relates to a method in which a water sample containing dissolved hydrocarbon fuel to be identified is contacted with a fiber optic element adapted to adsorb a hydrocarbon fuel on at least a portion of the element, for a time sufficient to adsorb a characterizing amount of the fuel from the water sample. The fiber optic element containing adsorbed hydrocarbon fuel is then removed from the water sample, and then at least the portion of the fiber optic element containing adsorbed fuel is immersed in or surrounded with water. The adsorbed hydrocarbon fuel is allowed to desorb from the fiber optic element while the rate of desorption of the fuel from the fiber optic element is measured by a fiber optic chemical sensor system of which the fiber optic element is a part.

Abstract: A collection receptacle for gathering leaves, twigs and the like for use with a plastic bag which includes an open cylindrical base having a scraper tray attached thereto and extending therefrom with integral handles and with a handle mounted to the base opposite the tray. A plastic bag is carried outside the cylindrical base and is retained thereon by frictional engagement between the handle and base and tray and base. The receptacle is preferably formed of three pieces of sheet plastic preferably retained in assembled condition by pins or a suitable adhesive, the nature of the securing determining the capability of disassembly for storage.