Table 1.

Metabolomics analytical platforms.

Technique	Characteristics	Advantages	Disadvantages	References
NMR	Nuclear magnetic resonance (NMR). 1D/2D 1H NMR usually employed in metabolomics studies.	Brief analysis time. Absolute metabolite quantification. High reproducibility. Intrinsically a quantitative technique since the signal strength is directly correlated with metabolite concentrations.	Its relatively low sensitivity can miss low-abundance metabolites. Signal overlapping due to the lack of a prior separation system. Typically, nonselective analysis is done with NMR. Major complications are presented by peak overlaps from numerous measured metabolites.	[28,29]
GC-MS	Gas chromatography–mass spectrometry (GC-MS). Volatile metabolites or those rendered volatile can be analyzed by GC-MS.	Relatively cheap. Better stability and separation efficiency. Being able to monitor highly hydrophobic and volatile compounds not ionized in the ESI source of LCMS/MS.	Unable to directly analyze nonvolatile, polar, or thermally labile drugs. Many biological substances are either too big or too polar to be examined using this method.	[30,31,32,33]
LC–MS/MS	liquid chromatography–mass spectrometry (LC–MS). High sensitivity. Biofluids like urine can be introduced directly into the LC system. Multidimensional can study the metabolome and lipidome in the same run.	Multidimensional—can study the metabolome and lipidome in the same run. High sensitivity. Biofluids like urine can be introduced directly into the LC system.	Greater operational costs. Lower concentration sensitivity. More restricted sample throughput.	[34]
LC–MS–NMR	Liquid chromatography-(LC)–mass spectrometry (MS)–nuclear magnetic resonance (NMR) Good spectral resolution and excellent metabolite identification ability.	Good spectral resolution. Excellent metabolite identification ability.	Different rates of exchange with deuterium are possible for analytes having exchangeable or “active” hydrogens since NMR uses deuterated solvents. The analyst should be aware of this possibility since it might cause a number of clustered molecular ions. The NMR component has high sample mass requirements.	[35,36,37]