Abstract Oxytocin is an important peptide, and it was chosen as the target analyte of the purity metrological international comparison, representing the type of peptide with molecular weight <5000, cross-linking, and non-modification. A quantitative nuclear magnetic resonance method with deconvolution was established to measure the purity of the oxytocin sample containing many structurally similar impurities. Appropriate internal standard (acesulfame potassium), solvent (deuterium oxide), quantitative peak (phenyl protons at chemical shift=7.1) and experimental parameters were selected. Through deconvolution analysis, the areas of three impurity peaks overlapping with the quantitative peak were obtained. After deducting the areas of impurity peaks, the purity of the oxytocin sample was accurately determined. The mentioned method was applied to participate in that international comparison, and its result (785.8mg/g, with expanded uncertainty of 15.4mg/g) was consistent with the reference value of the comparison (787.2mg/g, with expanded uncertainty of 12.9mg/g). Moreover, compared with other common methods, the method has the advantages of simple operation, short analysis time and low cost. The results show that the mentioned method is an accurate, rapid and simple method for peptide purity determination.
HUANG Ting,ZHANG Wei,LI Hong-mei. Measurement of the Purity of Oxytocin by Quantitative Nuclear Magnetic Resonance Method with Deconvolution[J]. Acta Metrologica Sinica, 2023, 44(8): 1298-1302.
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2023, Vol. 44 
