(±)17-HDHA is an autoxidation product of docosahexaenoic acid (DHA, Cay-90310) in vitro. It is also produced from incubations of DHA in rat liver, brain, and intestinal microsomes. 17(S)-HDHA (Cay-10009799) could be produced by enzymatic oxidation of DHA using soybean lipoxygenase (LO) and is the putative product of mammalian 15-LOs. 17(S)-HDHA was shown to be an inhibitor of U-46619 (Cay-16450) -induced rabbit and rat aortic smooth muscle contraction with IC50 values of 4.9 and 7.2 µM, respectively. (±)17-HDHA is a potential marker of oxidative stress in brain and retina where DHA is an abundant polyunsaturated fatty acid. (±)17-HDHA MaxSpec(R) standard is a quantitative grade standard of (±)17-HDHA (Cay-33650) that has been prepared specifically for mass spectrometry or any application where quantitative reproducibility is required. The solution has been prepared gravimetrically and is supplied in a deactivated glass ampule sealed under argon. The concentration was verified by comparison to an independently prepared calibration standard. This (±)17-HDHA MaxSpec(R) standard is guaranteed to meet identity, purity, stability, and concentration specifications and is provided with a batch-specific certificate of analysis. Ongoing stability testing is performed to ensure the concentration remains accurate throughout the shelf life of the product. Note: The amount of solution added to the vial is in excess of the listed amount. Therefore, it is necessary to accurately measure volumes for preparation of calibration standards. Follow recommended storage and handling conditions to maintain product quality.