Infrared Determination of Inorganic Nitrates by the Pellet Technique; Infrared Determination of Two Inorganic Nitrates in the Presence of Each other

Abstract

The quantitative determination of inorganic nitrates by the pellet technique was investigated. Methods are described for the determination of sodium, potassium, barium, and strontium nitrates. In these methods the nitrate is weighed into a small tared mortar, 300 mg of potassium bromide is added, the pellet is formed, and absorbances are determined at the appropriate peak. The peaks recommended for sodium, potassium, barium, and strontium nitrates are 836, 825, 730, and 737 cm−1, respectively. Methods are also proposed for the determination of two nitrates in the presence of each other. For the analysis of a mixture of sodium nitrate and potassium nitrate, measurements are made for sodium nitrate at 836 cm−1 and for potassium nitrate at 825 cm−1. For the analysis of a mixture of barium nitrate and strontium nitrate, measurements are made for barium nitrate at 730 cm−1 and for strontium nitrate at 737 cm−1. The methods for the determination of two nitrates can be used down to a ratio of 1 to 20. For lesser ratios the errors are rather large. Sulfates do not interfere with any of the procedures.