Liquid chromatography with tandem mass spectrometry (LC/MS/MS), although an old technique, is now commonly seen in the clinical laboratory. LC/MS/MS has several advantages over GC/MS:
- Sample pre-treatment or extraction is reduced in LC/MS/MS and can sometimes be eliminated.
- There is usually no need to derivatize the analyte to make it more volatile and less polar. LC/MS/MS can quickly analyze polar compounds.
- LC/MS/MS also offers a much higher sensitivity and specificity.
GC/MS does have some advantages over LC/MS/MS. Most notably speed and lower cost. GC/MS also gives more structural information due to the high degree of fragmentation seen in electron impact ionization. However, due to the above advantages, LC/MS/MS has begun replacing GC/MS in clinical laboratories.
