Patent ID: 8765911

Claim:
A method comprising; (a) providing a batch of glatiramer acetate; (b) obtaining one or more samples of the batch of glatiramer acetate; and (c) measuring, in at least one of the one or more samples of the batch, the level of diethylamide-modified fragments selected from the group consisting of: fragments having a diethylamide-modified alanine, fragments having a diethylamide-modified lysine, fragments having a diethylamide-modified glutamic acid, and fragments having a diethylamide-modified tyrosine using a method that comprises: (i) cleaving the glatiramer acetate to generate fragments; (ii) combining the fragments with detectably labeled diethylamide-modified peptide standards; (iii) fractioning the mixture of fragments and detectably labeled diethylamide-modified peptide standards to generate subpopulations; and (iv) detecting the fragments and detectably labeled diethylamide-modified peptide standards in one or more subpopulations by a method selected from mass spectroscopy analysis, MS-MRM detection, tandem mass spectrophotometry (MS/MS), and NMR.