Improvement of Sample Retention Time for Nessler's Reagent Spectrophotometric Method for Ammonia in Workplace Air
The method for determining ammonia based on the standard Determination of Inorganic Nitrogen Compounds in Workplace Air Toxic Substances was improved.0.005 mol/L sulfuric acid was used as the absorption solution to study the optimization of ammonia storage time.Nessler's reagent was used as the color reagent to measure absorbance at a wavelength of 420 nm.According to the Guidelines for the Development of Occupational Health Standards Part 4:Methods for the Determination of Chemical Substances in Workplace Air(GBZ/T 210.4-2008)sample accuracy and stability test regulations,the influence of storage time on its results was studied.Through experiments,it has been proven that ammonia in the workplace air is absorbed by a 0.005 mol/L sulfuric acid solution,collected using a large bubble absorption tube.In an alkaline solution,ammonia reacts with Nessler's reagent to form a yellow complex,and the absorbance is measured at a wavelength of 420 nm.The storage time of the collected samples can be extended to at least 7 days.
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