Figure 3: GC chromatograms of fatty acid methyl esters in a standard and as part of a study of the effects of produced water from oil and gas production on cod [17]. FAME were analysed on an HP 6890 GC FID equipped with a 7683 autosampler. The GC column was a ZB wax+ (Phenomenex, U.S.A.). The column length was 30 m with an internal diameter of 0.32 mm. The column temperature began at 65°C where it was held for 0.5 minutes. The temperature was ramped to 195°C at a rate of 40°C/min, where it was held for 15 minutes and then ramped to a final temperature of 220°C at a rate of 2°C/min. This final temperature was held for 0.75 minutes. The carrier gas was hydrogen flowing at a rate of 2 ml/minute. The injector temperature started at 150°C and ramped to a final temperature of 250°C at a rate of 120°C/minute. The detector temperature stayed constant at 260°C. Peaks were identified using retention times from a mixture of standards purchased from Supelco, 37 component FAME mix (Product number 47885-U), Bacterial acid methyl ester mix (product number 47080-U), PUFA 1 (product number 47033), and PUFA 3 (product number 47085-U). Chromatograms were integrated using the Varian Galaxie Chromatography Data System, version A quantitative standard purchased from Nu-Chek Prep, Inc. (product number GLC490) was used to check the GC column performance about every 300 samples (or once a month).