This standard describes the determination scope and theory of nitrogen in calcium metal, and specifies the analytical procedures, calculation result and method precision.
It is applicable to the determination of nitrogen in calcium metal, in range from 50 to 4 500μg/g.
2 Method summary
Dissolve the specimen with hydrochloric acid (1+1), transfer the solution to a distiller, add sodium hydroxide solution for vapor distillation, absorb with dilute sulfuric acid, then add Nessler reagent to the evaporated solution for color development, and then measure its absorbance at 440nm spectrophotometer wavelength.
3 Reagents
3.1 Unless otherwise specified, the analytically-pure reagents are used for the purpose of this standard.
3.2 The water is ammonia-free water: add 5mL concentrated sulfuric acid into 10L deionized water, mix the solution well and distill.
3.3 Sodium hydroxide solution: 40% (m/V).
3.4 Hydrochloric acid (1+1): with density of 1.19g/cm3.
3.5 Sulfuric acid (0.005M): with density of 1.84g/cm3.
3.6 Nessler reagent.
3.6.1 Dissolve 35g of potassium iodide with water and dilute the solution to 100mL.
3.6.2 Dissolve 17g of mercuric chloride with water and dilute the solution to 300mL.
3.6.3 Dissolve 120g of sodium hydroxide with water and dilute the solution to 600mL.
GB/T 10267.5-1988 The following standards are cited：
GB/T 10267.5-1988 Cited by the following standards：
