Practical Aspects of Analysis at High Mass

Three types of carbohydrate sample have been reported to give data above mass 4000, namely, permethylated polysaccharides, permethylated glycosphingolipids, and naturally acylated forms of a mycobacterial O-methyl-D-glucose polysaccharide. All are hydrophobic, and desorption is probably facilitated by their inability to form strongly hydrogen-bonded aggregates, either with themselves or with the matrix. 

The quality of data recorded from weak, high-mass-ion beams can usually be improved by the use of signal averaging. The computer software necessary is now available from the mass spectrometer manufacturers. Although signal averaging has not yet been applied to high-mass-carbohy- 

---