The analyses were performed using gas chromatography (GC) and liquid chromatography (LC) combined with mass spectrometry (MS). 
gas chromatography
The analyses were performed using gas chromatography (GC) and liquid chromatography (LC) combined with mass spectrometry (MS). 
liquid chromatography
The analyses were performed using gas chromatography (GC) and liquid chromatography (LC) combined with mass spectrometry (MS). 
mass spectrometry