消解仪－麝香草酚分光光度法测定水中总氮

采用消解仪替代高压蒸汽灭菌器消解水样,用麝香草酚分光光度法替代紫外分光光度法测定总氮.试验表明,方法在0mg/L～10.0mg/L范围内线性良好,相关系数R为0.9999;方法检出限为0.04mg/L;测定低、中、高质量浓度的标准溶液,RSD为1.1% ～5.5%;对3份实际水样进行加标回收试验,回收率为94.6% ～98.2%,测定总氮标准品,结果在保证值范围内;用该方法与国标方法同时测定水样,测定结果的相对偏差〈5%.

Determination of Total Nitrogen in Water by Digestion Instrument with Thymol Spectrophotometry

Total nitrogen in water was determined by digestion instrument-thymol spectrophotometl7 in stead of autoclave digestion UV spectrophotometl7. The results showed that there was a good linear relation between the concentrations of nitrate-N and the absorption values in the range of 0 mg/L - 10.0 mg/L and the correlation co- efficient was 0. 999 9. The method detection limit was 0.04 mg/L. When determining the standard solution of low, medium and high concentrations, the RSDs ranged from 1.1% to 5.5 % , and the recovel7 rates were 94.6% - 98.2%. The relative deviation between the current method and the national criteria was less than 5%.