T/CAIA SH024-2025 Determination of Total Nitrogen in Surface Water by Automatic Digestion UV-spectrophotometry
T/CAIA SH024-2025 Determination of Total Nitrogen in Surface Water by Automatic Digestion UV-spectrophotometry
Basic Information
Scope
Scope: This document describes the method for determining the total nitrogen content using an automatic dissolution ultraviolet photometry method. This document is applicable to the determination of total nitrogen content in surface water, with a detection limit of 0.05 mg/L (calculated as N) and a measurement range of 0.20 mg/L to 7.00 mg/L. Other types of water samples can refer to this document for implementation. Main technical content: In an alkaline medium, under high temperature and high pressure conditions, potassium persulfate converts the nitrogen in nitrogen-containing compounds into nitrate nitrogen. The total nitrogen content is determined using ultraviolet photometry. A calibration curve is established by the absorbance value after blank subtraction and the corresponding total nitrogen content.