DETERMINATION OF NITRATE IN CARBON-BLACK BY USING A NITRATE-SELECTIVEELECTRODE

In this paper, a rapid and simple potentiometric method, based on the use of a nitrate-selective electrode, is described for the determinati on of nitrate in Carbon Black. The extraction of nitrate from the Carb on 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 measurem ent technique was used. The precision and accuracy of the developed pr ocedure, expressed in terms of relative standard deviation (2.5%) and average percentage of spiked recoveries (100.8) were good. Adequate ag reement (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 Car bon Black from different European factories.