What are the commonly used solvents for polypeptides in LCMS or MS analysis?

The preferred solvents are deionized distilled water, chromatographic grade acetonitrile, chromatographic grade methanol, and sometimes the analytically pure DMF, analytically pure DMSO, etc. Given the use of DMSO may affect the ionization effect of some polypeptide samples during dissolution thus resulting in poor test results, DMSO is only used if other solvents do not work well in dissolution or if the polypeptide cannot be dissolved with the pH having been adjusted.

How to save synthetic polypeptide?

For a long-term storage, polypeptides are generally protected from the light, at -20℃, and for a short-term storage, polypeptides are stored at 4℃. It can be transported at room temperature for a short time. Polypeptides are very stable at -20 ° C, especially freeze-dried and stored in a desiccator, and lyophilized polypeptides can be placed at room temperature environment before being exposed to air. When there is a reduction in humidity effects, and it is not possible to freeze and dry, it is best to be stored by small working samples.

For polypeptides containing Cys, Met or TrP, the deoxygenation buffer is essential for the dissolution because such polypeptide is easily oxidized by air, and the oxidation will also be weaken under the influence of nitrogen or argon in the air before the container is sealed.