The quantitation of plasma phytanic acid by mass fragmentography.

Plasma phytanic acid has been quantitated by mass fragmentography after its successive reduction and derivatization to the corresponding t-butyldimethylsilyl ether. The latter was estimated by selective ion monitoring of its characteristic (M-57) ion (M/z 355). The technique has the advantage of being more rapid, specific and sensitive than existing methods, permitting the determination of phytanic acid at levels greater than 5 mug/ml plasma.