GLC microdetermination of indomethacin in plasma

A GLC method utilizing an electron-capture detector is described for analysis of indomethacin in blood plasma. Indomethacin is extracted with ethyl acetate from plasma buffered to pH 5.0. The ethyl acetate is evaporated to dryness, and indomethacin is derivatized to a pentafluoropropionyl ester prior to chromatography. A GLC standard is used for peak height quantitation of indomethacin. The extraction efficiency from plasma is 92 +/- 3%, and as little as 1 ng of indomethacin can be quantitatively determined.