Determination of Total Nitrogen in Water and Wastewater by Continuous Flow Analysis and Spectrophotometric Method

Applicability of continuous flow analysis and spectrophotometric method to measure total nitrogen in water and waste water was studied. Calibration results of 6 laboratories showed good linear regression in concentration range between 0 mg / L and 10. 0 mg / L with correlation coefficient varied from 0. 999 6 to 0. 999 9. The method detection limit was 0. 04 mg / L and the quantitation limit was 0. 16 mg / L. The test results of certified reference material was in the permission range,RSD ranged from 0. 4% to 9. 6%. The recovery rate of real water samples was between 92. 0% ~ 111% 。Therefore the aforesaid method shows no significant difference compared with national standard method. The interference factor and elimination method was discussed.