The salicylate method for determining nitrate in water is based on the reaction of salicylate with nitronium ions, which produces a nitrobenzoic compound. In alkaline conditions, the nitrobenzoic compound converts to a quinoid compound that produces a yellow color. The color is measured spectrophotometrically at a wavelength of 410 nm.
Here are some details about the salicylate method:
Reaction: The nitrate in the sample extract nitrates salicylic acid in a sulfuric acid medium.
Color: The nitro-compound formed is an intense yellow color in alkaline solution.
Wavelength: The color is measured spectrophotometrically at a wavelength of 410 nm.
Concentration: The method can be applied to NO3- concentrations between 0.15 and 15 mg. L-1.
Calibration curve: A calibration curve of absorbance as a function of the concentration of NO3 is created from the corrected absorbances of the standard solutions.
Dilution: If the absorbance readings are much larger than 1, or if the water sample's absorbance is much higher than the highest standard solution, the samples need to be diluted.
Sodium salicylate is a chemical compound that contains sodium and is often used in various scientific applications.
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