After 17 soil samples collected from 17 regions in China were extracted by deionied water, the continuous flow injection analyzer FIA star 5000 and traditional phenol disulfonic acid method were employed to analyze nitrate concentration and N recover rate respectively. The accuracy of both methods was similar, whereas the precision of phenol disulfonic acid method were higher than that of the flow injection analysis method. The recovery rate and relative standard variance of the phenol disulfonie acid method were 98.39％～100.21％, and 0.43％～9.02％ with a mean of 4.43％, respectively, and 98.93％～101.17％, 0.13％～13.82％ with a mean of 5.21％ for flow injection analysis method. Relatively, flow injection analysis method had distinct advantages, such as simple manipulation, higher efficiency, etc.. Moreover, one sample could be used to determine ammonia-N and nitrate-N at the same time in flow injection analysis method. These suggested that flow injection analysis method should be more available in determination of large amount of soil samples.%采自全国17个地区的17个土壤样品用水浸提后,分别采用FIAstar 5000 Analyzer型流动注射仪和酚二磺酸比色法测定其硝态氮的含量,然后分析两种方法测定结果的准确度、精密度及其回收率.结果表明,酚二磺酸比色法准确度和精密度都高,标准样品加入回收率为98.39%～100.21%,相对标准差为0.43%～9.02%,平均为4.43%.流动注射法精密度不如酚二磺酸法比色法,但准确度与酚二磺酸比色法一样,标准样品加入回收率为98.93%～101.17%,相对标准差为0.13%～13.82%,平均为5.21%.相对而言,流动注射法操作简便,分析效率高,一份样品还可以同时测定氨态氮,极大地提高了分析速度,因此有利于大批量样品分析.
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