Permethylated, High-Mass Samples

Pjq g jjjg Fab. Map Lartosaminoglycan Sample Isolated from Normal 

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The experimental challenge for MS is how to get a stream of molecular ions into the high vacuum of the instrument in a suitable form for mass analysis. Sample ionization techniques have proven to be the key to successful applications of MS to biomolecular problems. Most compounds, especially high RMM and polar materials, have a very low vapour pressure and do not easily evaporate, even under the high vacuum in the mass spectrometer. With small compounds it is usually possible to produce volatile versions by careful chemical derivitization e.g. permethylation, acylation, esterification), and this is the basis for most routine chemical applications of MS. However, this is rarely satisfactory for larger biomolecules, and alternative strategies have to be adopted. 

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