1 Subject content and applicable scope
This standard specifies method for determining nitrogen in petroleum additives by Kjeldahl method.
This standard is applicable to petroleum additives. There is no interference from metallic elements such as calcium, barium, zinc and magnesium, and non-metallic elements such as sulfur, phosphorus, oxygen and chlorine. This method is applicable to concentrations from 0.01% to 2% (m/m).
2 Summary of method
The sample is digested with mercury as catalyst in sulfuric acid. After all the nitrogen in the sample is converted into ammonium sulfate, excess sodium hydroxide solution is added before distillation. The ammonia generated by the reaction is absorbed by boric acid. The ammonia absorbed in boric acid is titrated with hydrochloric acid standard volumetric solution. Nitrogen in the sample is calculated using the volume of hydrochloric acid standard volumetric solution consumed.
3 Apparatus
3.1 Kjeldahl flask: 1000mL.
3.2 Kjeldahl digestion and distillation unit.
3.3 Glass beads: about 5mm in diameter.
1 Subject content and applicable scope
2 Summary of method
3 Apparatus
4 Reagents
5 Preparations
6 Test procedure
7 Calculation
8 Precision
9 Report
Additional explanation:
