Determination of nitrate in Carbon Black by using a nitrate-selective electrode

Abstract

In this paper, a rapid and simple potentiometric method, based on the use of a nitrate-selective electrode, is described for the determination of nitrate in Carbon Black. The extraction of nitrate from the Carbon Black was effected by stirring the samples for 5 min in hot water. A conditioning solution for removing interfering anions and adjusting the ionic strength has been developed. The standard additions measurement technique was used. The precision and accuracy of the developed procedure, expressed in terms of relative standard deviation (2.5%) and average percentage of spiked recoveries (100.8) were good. Adequate agreement (r= 0.999) was found between results obtained by the proposed method and those of a spectrophotometric method based on brucine, the reference technique, when applied simultaneously to 48 samples of Carbon Black from different European factories.