Suitable mobile phases including hexane, heptane, 2-propanol and ethanol in different mixtures can be used in normal phase mode. Recommended mobile phase: hexane/2-propanol (90/10, v/v). Modifiers: N,N-diethylamine for basic samples, trifluoroacetic acid for acidic samples. (NOTE: minimize use of a modifier; typical use is 0.1 %; maximum 0.5%.). In NP mode, retention time is generally shorter with higher alcohol content. Ethanol will shorten the retention time compared to 2-propanol.