Non-halogenated molecules having 10-30 carbons including aliphatic, aromatic, saturated, unsaturated (and combinations thereof) alcohols, ketones, organic acids, organic acid salts, sulfonated derivatives, and/or other derivatives are used as tracers to measure oil and/or water fluid returns, such as from a hydraulic fracturing job. The non-halogenated molecules may be combined with substrates and introduced into a subterranean location, desorbed and recovered from the subterranean location with a fluid, reacted with a reagent (e.g. pentafluoro benzyl chloride) to give a derivatized tracer. Alternatively, the tracer molecule release can be delayed by use of an emulsion or a coating that allows slower diffusion of the tracer into the fluid. The presence of the derivatized tracer is then detected in the recovered fluid. A different non-halogenated tracer may be used for each hydraulic fracturing stage, e.g. to determine from which fracturing stage water is produced and from which oil is produced.