Patent ID: 7531358
Filing Date: 2009-05-12
Classification: G01N,Y10T

Abstract:
1. A method of quantifying polysorbate in a sample containing a physiologically active protein, comprising: adding an aqueous organic solvent to the sample containing a physiologically active protein, thereby forming a precipitate of the physiologically active protein, removing the precipitate from the sample to thereby obtain a cleared sample, and thereafter adding an ammonium thiocyanate/cobalt nitrate reagent (CoSCN reagent) to the cleared sample, thereby forming a resulting cobalt thiocyanate complex, to thereby obtain a sample containing the cobalt thiocyanate complex; adding a non-aqueous organic solvent to the sample containing the cobalt thiocyanate complex to thereby obtaining a mixture of non-aqueous organic solvent and the sample containing the cobalt thiocyanate complex; shaking the mixture to extract the cobalt thiocyanate complex into a non-aqueous organic solvent layer thereby obtaining a non-aqueous organic solvent layer containing the cobalt thiocyanate complex; collecting the non-aqueous organic solvent layer containing the cobalt thiocyanate complex; quantifying the cobalt thiocyanate complex in the non-aqueous organic solvent layer by absorbance measurement with a spectrophotometer by measuring absorbance at 320 nm; and quantifying polysorbate in the sample by calculating the amount of polysorbate from the amount of the cobalt thiocyanate complex.