Potentiality of proton nuclear magnetic resonance and multivariate calibration methods for the determination of dermatan sulfate contamination in heparin samples

A H-1 NMR method for the quantification of dermatan sulfate impurities in h eparin industrial samples is proposed. The method is based on the analysis of H-1 NMR spectral data by multivariate calibration. The H-1 NMR spectra o f heparin and dermatan sulfate standards showed characteristic profiles. Th us, differences in the methyl peaks of acetamido groups of heparin and derm atan sulfate were greatly advantageous for the analysis. Other hydrogens of the sugar ring were also relevant in this study. Thus, the determination o f dermatan sulfate by multivariate calibration depended on all these differ ences. Partial least squares regression (PLS) was chosen as the calibration method. In addition, a data standardization procedure was developed in ord er that H-1 NMR spectra registered with different instruments operating und er different measurement conditions were comparable. The quantification of dermatan sulfate in the samples was satisfactory, with an overall predictio n error of 6%.