Preparation of [3H]Phosphoinositol Standards and Conversion of [3H]Phosphoinositides to [3H]Phosphoinositols

Any chromatographic procedure for the separation of phosphoinositols will require a supply of standards, both for validation of the technique and identification of the products. Tritium-radiolabeled standards are commercially available in 1–2 μCi quantities for Ins(1,3,4,5)P₄ , Ins(1,4,5)P₃ , Ins(1,3,4)P₃ , Ins(1,4)P₂ , Ins4P, and Ins1P. Although such standards can often be purchased as a standard mixture, it is preferable to purchase them unmixed so they can be used as starting materials for other standards. At present, other standards that are unavailable commercially must be prepared as required using chemical or enzymological methods.