6-keto Prostaglandin F1alpha (6-keto PGF1alpha) is the inactive, non-enzymatic hydrolysis product of PGI2 (Cay-18220). 6-keto PGF1alpha serves as a useful marker of PGI2 biosynthesis in vivo. When [3H]-PGI2 is injected into healthy human males, 6.6% of the radioactivity is recovered from urine as [3H]-6-keto PGF1alpha. 6-keto PGF1alpha MaxSpec(R) standard is a quantitative grade standard of 6-keto PGF1alpha (Cay-15210) 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 6-keto PGF1alpha 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.