Formulation: A solution in ethanol (1 μg/ml each compound)
Shelf life (days): 1825
Notes: This mixture contains a collection of vasoactive eicosanoids, including the characteristic metabolites of both prostaglandin I2 (PGI2; Item No. 18220) and thromboxane A2 (TXA2), as well as several additional HETE and EET metabolites produced by platelets and the cytochrome P450 pathway of arachidonic acid metabolism. The mixture is supplied in an amber ampule in which the headspace has been purged with argon to prevent lipid oxidation. This product has been designed for direct use in LC-MS applications. The solution may be serially diluted for preparation of calibrators and QC standards and/or used directly as a system suitability standard or tuning standard. After opening, we recommend that the mixture be transferred immediately to a 1 ml glass screw cap vial, to prevent solvent evaporation, and stored at -20°C. The mixture should be discarded after multiple freeze/thaw cycles.Whereas PGI2 is a potent vasodilator and inhibitor of human platelet aggregation, TXA2 causes irreversible platelet aggregation and contraction of vascular and bronchial smooth muscle. Because both are rapidly hydrolyzed and metabolized, TXB2 (Item No. 19030), 11-dehydro TXB2 (Item No. 19500), and 6-keto PGF1α (Item No. 15210) serve as useful markers for their synthesis.{1410,439} Certain HETEs and EETs have been shown to either inhibit platelet activation or regulate vasoconstriction.{498,567,31110,7827,1111,5318,792}