Figure 2: TLC/FID chromatograms of lipid classes in a standard and as part of a study of the effects of produced water from oil and gas production on cod [17]. Lipid class composition was determined after a three-step development on Chromarods (Figure 1). Lipid extracts were applied to the Chromarods and focused to a narrow band using 100% acetone. The first development system was hexane : diethyl ether : formic acid (98.95 : 1.0 : 0.05). The rods were developed for 25 min, removed from the solvent system for 5 min, and replaced for 20 min and then partially scanned in the Iatroscan. The second development was for 40 min in hexane : diethyl ether : formic acid (79 : 20 : 1) after which the rods were partially scanned. The final separation had two steps, the first was development in 100% acetone for two 15 min time periods, then two 10 min periods in chloroform : methanol : chloroform-extracted water (5 : 4 : 1), after which the rods were dried and their entire length scanned. Before using each solvent system the rods were placed in a constant humidity chamber. The Chromarods were calibrated using standards (e.g., Figure 1) from Sigma Chemicals (Sigma Chemicals, St. Louis, MI, USA).