Prostaglandins TBDMS deriv

Many GC-MS methods for prostaglandins utilize the more common El method rather than Cl. Both TMS [57-59] and TBDMS ether derivatives (see next section) are commonly employed as mixed derivatives with other types, e.g. oximes and methyl esters. As expected, the TMS derivatives provide multiple fragment ions, which aid specificity as discussed earlier. The TBDMS derivatives are generally chosen for sensitivity, much of the ion current being concentrated on only a few fragment ions. Diagnostic ions for methyloxime—methyl ester-TMS ether derivatives of 11 prostaglandins and thromboxane B2 have been tabulated by Kelly 60[. 

TBDMS derivatives found early application in prostaglandin and thromboxane analysis [77, 93, 94]. 

Further alkyidimethylsilyl derivatives have been evaluated in mixed derivatives for the GC—MS analysis of steroids [107-109] and prostaglandins and thromboxane Bj [110]. Although they have favourable properties, they generally provide no significant advantages over the TBDMS derivatives. 

Interest in the biosynthesis, metabolism and physiological roles of prostaglandins and related compounds has prompted extensive investigation of sensitive and selective analytical procedures. An early report in this area [302] described the preparation of TBDMS ethers of prostaglandin methyl esters and methyl ester-oximes by treating samples with 50 /il of TBDMCS (2 M in DMF) and 50 /il of imidazole (2 M in DMF) at 100 °C for 1 h). After cooling the, reaction mixture was applied to the top of a 0.5 X 3 cm column of Sephadex LH-20 swollen with heptane/ethyl acetate (3 1), and the derivatives were eluted with 4 ml of the same solvent. After evaporation of the solvent, samples were analysed by... 

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