This method describes detection of DG, OG, PG and NDGA.
The detection limit is 0.001% (m/m).
DG, OG, PG and NDGA are extracted from the fat by shaking
with methanol. The methanol layer is evaporated to dryness,
and the residue is dissolved in ethanol. The solution is
analysed by thin layer chromatography, and the spots are
visualized by spraying with phosphomolybdic acid solution.