Table 2. Variants of Mass Spectrometry (MS) and Their Advantages and Disadvantages.

Technique(s)	Important features	Advantages	Disadvantages	Ref
Accelerator mass spectrometry (AMS)	• Employed particle accelerator technology into a mass spectrometer.	• Small quantity of sample is sufficient	• High cost makes it less affordable	(82, 83)
	• Its detection range include ion currents of more abundant stable isotopes (e.g., 12C, 13C) to very rare radionuclides (e.g., 14C)	• Need less time for estimation	• Small sample size makes it prone to contamination
Liquid chromatography mass spectrometry	• Simple and robust technique for regular analysis	• Wide linear dynamic range	• Lower accuracy	(84, 85)
	• Able to detect nonvolatile compounds like sugar and proteins that cannot be detected in GC-MS	• Lower detection limit	• Isotopes cannot be detected
		• High precision and accuracy
Gas chromatography mass spectrometry	• Sample exposed to high temperature	• Analysis is faster and selectivity,	• Destructive method of analysis	(86−88)
	• Used for the detection of volatile compounds from sample	• Lower detection limits	• Only thermolabile compounds can be detected
	• Nonvolatile compounds like sugar can be detected after dertivatization
High resolution mass spectrometry	• Good for the identification of unknown samples	• Highly accurate and selective measurement	• Expensive analysis	(89)
	• Efficient for nontargeted analyses	• Able to detect mass accurately with even small change is detectable	• Data generated is hige and complex
			• Not suitable for regular analysis of known samples
Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry	• Traditional method for the identification of microorganisms	• Able to differentiate between phenotypic, genotypic, and biochemical properties	• In some cases, unable to differentiate between closely related species, e.g., E. coli, and Shigella	(90)
	• Sample is first ionized, and segregated based on mass-to-charge ratio	• Reduced analysis time	• Lack sufficient spectra in database
	• Measurement is done by determining with time-of-flight
Inductively coupled plasma mass spectrometry	• Used to measure the element level in sample	• Wide analytical range with lower detection limit	• High cost of investment and operation	(91)
	• Sample converted to aerosol from liquid	• Need small quantity of sample	• Need experts for operation
		• High throughput with multielement detection
Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry	• It is also known as SELDI-TOF-MS-based ProteinChip System	• It employes chromatographic separation techniques	• Low detection precision for individual proteins from complex	(92, 93)
	• It is modified form of MALDI-TOF	• Less time-consuming and high through put system	• Low mass resolution
	• Proteomic profiling of biological fluids
Tandem mass spectrometry	• Two or more MS units are interconnected with quadrupoles and TOF analyzer	• Highly specific	• High operational cost	(79, 94, 95)
	• Effective in analyzing complex mixture	• Low signal-to-noise ratio	• Limited sample through put
		• Able to detect covalent modifications in proteins
		• Sensitive and reproducible