多参数分析仪测定煤化工废水总氮方法OA

To address the problems of cumbersome operation,long analysis time,and high reagent consumption associated with traditional methods for determining total nitrogen(TN)in coal chemical wastewater,and to meet the needs for industrial batch detection,a method was established by coupling a multi-parameter analyzer with a rapid digestion instrument.Alkaline potassium persulfate was used as the digestion reagent,and the digestion condition was set at 122℃for 30 min.After cadmium column reduction in a pH=7.5 imidazole buffer system,the absorbance was measured at 550 nm after diazo coupling color development.The results demonstrated that TN concentration had a good linear relationship in the range of 0-1.00 mg/L,with a correlation coefficient R2=0.999 8 and a detection limit of 0.03 mg/L(better than 0.05 mg/L of the HJ 636-2012 standard).The average blank absorbance was 0.007 9,the cadmium column reduction rate was 93.77%-103.64%,oxidation-reduction rate of TN was 98.0%-103.5%,and the spiked recovery rate of actual samples was 96.3%-103.9%.The relative standard deviations at TN mass concentration of different sample ranged from 0.014%to 0.191%.This method is highly automated,environmentally friendly,and economical,filling the technical void in rapid TN detection of complex matrix wastewater,and is well suited for efficient application in batch monitoring of coal chemical wastewater.