1 Application Scope
This standard specifies the alkaline potassium persulfate digestion UV spectrophotometric method to determine total nitrogen in water.
This standard is applicable to determination of total nitrogen in surface water, underground water, industrial wastewater and domestic wastewater.
Where the sample volume is 10ml, detection limit of this method is 0.05mg/L and the determination range is 0.20~7.00mg/L.
2 Normative References
The following standards contain provisions which, through reference in this standard, constitute provisions of this standard. For undated references, the effective edition of the normative document applies.
HJ/T 91 Technical Specifications Requirements for Monitoring of Surface Water and Waste Water
HJ/T 164 Technical Specifications for Environmental Monitoring of Groundwater
3 Terms and Definitions
For the purpose of this standard, the following term and definition applies.
Total nitrogen (TN)
The sum of dissolved nitrogen and nitrogen in suspended solids of the determined sample under conditions specified in this standard, including the nitrogen nitrite nitrogen, nitrate nitrogen, inorganic ammonium salts, dissolved ammonia and the nitrogen in a majority of organic nitrogen compounds.
4 Method Principle
Foreword I
1 Application Scope
2 Normative References
3 Terms and Definitions
4 Method Principle
5 Interference and Elimination
6 Reagents and Materials
7 Instruments and Equipment
8 Sample
9 Analytical Procedures
10 Result Calculation and Expression
11 Precision and Accuracy
12 Quality Assurance and Control
13 Precautions
Appendix A (Informative) Determination Method for Nitrogen Content of Sodium Hydroxide and Potassium Persulfate
