In this article, we describe the first use of trisulfonated sodium amine as a sulfating reagent for preparing pectin sulfate in aqueous solution. The main reaction parameters that were expected to affect the degree of substitution (DS) were studied. The optimal reaction conditions for the synthesis of pectin sulfate were found to be as follows: the pH of the reaction medium, the reaction temperature, the reaction time, and the ratio of the mole of sodium nitrite (nNaNO2) to the mass of pectin (mpectin) were 6, 60 degrees C, 12 h, and 2.5/190 mol/g, respectively. Pectin and pectin sulfate were characterized by Fourier transform infrared (FTIR) spectroscopy and 13C-NMR. The FTIR spectra showed the characteristic absorptions of sulfate ester bonds at 1264 and 830 cm-1. Furthermore, the anticoagulant activity of pectin sulfates with different DSs, concentrations, and molecular weights were investigated with respect to the activated partial thromboplastin time (APTT), thrombin time (TT) and prothombin time. The clotting assay indicated that the pectin sulfate prolonged APTT and TT through inhibition of the activity of antithrombin. These results suggest that the introduction of sulfate groups into the pectin structure improved its anticoagulant activity. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012