Mass Spectrometry

Mass spectrometry determines the molecular mass of a compound, and through analysis of its characteristic fragmentation pattern, provides additional...

Mass spectrometry determines the molecular mass of a compound, and through analysis of its characteristic fragmentation pattern, provides additional structural information about the connectivity and substitution pattern of the molecule. A sample is ionised (most commonly, for pharmaceutical compounds, by electrospray ionisation, a soft ionisation technique that produces predominantly intact molecular ions with minimal fragmentation) and the resulting ions are separated and detected according to their mass-to-charge ratio, yielding a mass spectrum in which the molecular ion peak (commonly observed as [M+H]⁺ in positive-ion mode or [M−H]⁻ in negative-ion mode) directly indicates molecular weight, while characteristic fragment ions arising from cleavage at particularly labile bonds provide corroborating structural evidence.