Abstract
Infrared absorption spectroscopy was applied to the determination of five brominated salicylanilides (3, 5, 4'-tri; 5, 4'-di; 5-mono; 3, 5, 2', 4'-tetra; 3, 5-di bromo salicylanilides) in their mixture. Nine wavelengths (10.87, 10.97, 11.11, 12.10, 12.82, 13.15, 13.32, 13.62 and 13.70 μ) were selected as key bands from the absorption spectrum of brominated salicylanilide solution in dimethyl formamide, and Beer's law was confirmed to be valid at these wavelengths. Nine equations of linear combination with absorbance and the amount of each component were derived from the absorbances of standard and sample solutions at these wavelengths, and the percent contents of the five brominated salicylanilides were calculated, respectively by the least square method using an electronic computer NEAC 2206.
Influences of the cell length and the concentrations of sample and standard solutions were negligible, and the absorbance of the standard could be fixed constant. Satisfactory reproducibility, precision and rapidity were obtained.
