Gas chromatography-flame-ionization detection (GC-FID) was used to quantify sterols and gas chromatography/mass spectrometry (GC/MS) was used to identify them. 
GC-FID
Gas chromatography-flame-ionization detection (GC-FID) was used to quantify sterols and gas chromatography/mass spectrometry (GC/MS) was used to identify them. 
GC/MS