Chromatography Forum

dear all,

in HPLC method for Related Substances we are using DMF as solvent for the sample preparation and we are getting a impurity peak which does not consistent response. Its response varies from 1% to 0.1%, with different make of DMF or with same make of DMF.

Has anyone else faced same problem with DMF as diluent.

Formic acid (most likely) or e reaction product of your sample/matrix with dimethylamine?

DMF decomposes on sitting around to various basic impurities. If your preparation and analysis is for basic components, then the decomposition of DMF may be your problem. If this is the case then DMF distillation may be one solution. Adsorption of the basic imputities from DMF using an SPE cartridge before sample preparation may be another solution.

Thanx for your reply