Gas chromatogram from ethanol-benzene extract of teak heartwood. Nine major compounds are indicated : peak 1 (Rt 17.4) and 4 (Rt 20.1) = desoxylapachol and its isomer; peak 2 (Rt 19.0) = palmitic acid; peak 3 (Rt 19.7) = lapachol; peak 5 (Rt 20.4) = unidentified compound 1, peak 6 (Rt 21.3) = tectoquinone; peak 7 (Rt 21.5) = unidentified compound 2, peak 8 (Rt 36.7) = squalene; and peak 9 (Rt 49.4) = tectol, IS = internal standard (heneicosane).