| 摘要 |
<p>A method for determining a concentration of a polysorbate species, such as polysorbate 20, polysorbate 40, polysorbate 60, or polysorbate 80, in a mixture comprises obtaining a test sample of said mixture, adding an internal standard, preferably azide, to said test sample, obtaining, with a spectrometer, a mid-infrared Attenuated Total Reflectance (ATR) spectrum of the test sample, e.g. by using and ATR-FTIR apparatus, identifying, from the reflectance spectrum, a wavenumber corresponding to the C=0 peak (e. g., 1735 cm-1), identifying, from the reflectance spectrum, a wavenumber corresponding to the internal standard, calculating the area under the curve for said C=O wavenumber, normalized by the internal standard, and comparing said area to a calibration curve to determine the concentration of polysorbate in said test sample.</p> |
