Analytical Methods for Determination of Total Nitrogen Content in the Process of Synthesizing Chemically Modified Rubber Materials

In this study, the total nitrogen content of natural rubber was determined to evaluate the effectiveness of deproteinization on the synthesis of chemically modified rubber materials. The remaining protein content in the obtained deproteinized natural rubber (DPNR) was analyzed as nitrogen content using the Kjeldahl method. In this method, the amine nitrogen present in the proteins was converted into ammonia, which was subsequently determined by chemical and physical methods. From the findings obtained from the examination of experimental conditions, a novel procedure was devised to determine the total nitrogen content in rubber using traditional titration, potential titration and UV-Vis spectrophotometry methods. The newly established techniques exhibited favorable results regarding the method detection limit (MDL) and limit of quantification (LOQ). Among these methods, spectrophotometry displayed exceptional sensitivity, enabling precise and accurate quantification of low nitrogen concentrations. Notably, these methods exhibit a high degree of recovery, ranging from 94.5% to 106.3%.