Guide to LC-MS and GC-MS techniques

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Chapter 1 covers liquid chromatography (LC), in which stationary phase is solid and the mobile phase is liquid. Mass spectroscopy has been used to measure the mass-to-charge ratio of ions. The principle of mass spectroscopy (MS) is the generation of a large number of ions of the compound and then separating them according to the mass-to-charge ratio (m/z). LC/MS has been used to find the molecular weight, structure, quantity, and identity of the compound under investigation. Chapter 2 focuses on Gas chromatography and its hyphenated form GC / MS, in which Gas chromatography (GC) is coupled with a mass spectrometer (MS). The combination has advantage of high-resolution capacity of gas chromatography to isolate closely related molecules and the capacity of MS to provide reliable data to analyze and evaluate the isolated compounds. GC has been used in estimation of volatile components, fatty-acids, mono and sesquiterpenes, hydrocarbons and sulphur compounds. Chapter 3 deals with specific example of plant extract of Tabernaemontana divaricata which was prepared by ultrasonication technique. In this chapter the researchers have attempted to identify all the possible phytoconstituents and their natural adducts by hyphenated techniques like Atmospheric Pressure Chemical Ionization (APCI) and Electron Spray Ionization (ESI). The isolated compounds are alkaloids, flavonoids, phenylpropanoids, triterpenoids, and essential oils classes of phytoconstituents. Hence, with this elucidation, the team believes that a further study using LC-MS/MS or LC-NMR would reveal confirmatory information about the extract. Chapter 4 focuses on GC-MS elucidation of different bioactive components in other plant Carissa congesta extract. The study revealed the presence of chemical entities of high and low molecular weight with differing proportions. The evaluation was based on the parameters of retention time, molecular formula, molecular weight and MS databases. The principal components found were unsaturated fatty acids and their esters followed by triterpenes, which play a significant therapeutic role. The components were found to be biologically and pharmacologically valued for their therapeutic importance. Chapter 5 covers GC- MS elucidation of Tabernaemontana divaricata. The extract has shown the presence of alkaloids, tannins, hormones, saponins, proteins, triterpenoids, flavonoids, phenylpropanoids, and reducing sugars. The chapter covers thirty-five components such as Styrene, D-glycero-D-manno-, Mesitylene, Z,Z-2,5-Pentadecadien-1-ol, Pterin-6-carboxylic acid, L-α-Terpineol, Cyclodecanol, (-)-Carvone, 2-Myristynoyl pantetheine, Cubedol, Benzophenone, Palmitic acid, 9-Octadecanoic acid(Z), Stearic acid etc. These chapters would further help students and researchers to get proper insight to the important phytoconstituents present in various plants.

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