杜马斯燃烧法与凯氏法测定畜禽粪便中氮含量的比较

为了比较杜马斯燃烧法与凯氏法测定畜禽粪便氮含量结果的异同,以取自中国不同地区的5种畜禽粪便和磺胺嘧啶标准物为试验材料,分别采用凯氏法和杜马斯燃烧法测定各种畜禽粪便的氮含量,并对上述2种氮含量测定结果进行比较分析。结果表明:5类畜禽粪便凯氏氮的质量分数范围为0.51%～3.19%,杜马斯燃烧氮的质量分数范围为0.51%～3.35%,2种方法测定值之间不存在显著性差异,变异系数CV均小于5%.畜禽粪便样品凯氏法与杜马斯燃烧法的测定结果呈显著性相关(R2=0.987,p<0.05),拟合直线的斜率与1以及截距与0之间均不存在显著性差异。因此,杜马斯燃烧法可以代替凯氏法测定蛋鸡、肉鸡、猪、奶牛和肉牛粪便中的氮含量。

Comparison of Kjeldahl and Dumas combustion methods for determination of nitrogen content in animal manures

In order to compare the determination features nitrogen content in animal manures by Dumas combustion method and Kjeldahl methods, five kinds of manures and one reference compound were analyzed for nitrogen concentrations using Kjeldahl and Dumas combustion procedures respectively. Statistical analysis was performed on Kjeldahl nitrogen and Dumas nitrogen values. The results showed that the Kjeldahl nitrogen content of animal manures ranged from 0.51% to 3.19% and the Dumas combustion nitrogen content ranged from 0.51% to 3.35%, there was no significant difference in the nitrogen mean values measured by the two methods, and the coefficient of variation of two methods were all below 5%. The nitrogen determined results from the all-samples population rendered a simple linear correlation (R2=0.987, p<0.05) between the two methods. All the Kjeldahl values as a function of Dumas values was close to 1:1 line. It was concluded that the Dumas combustion procedure is capable of replacing the Kjeldahl procedure for nitrogen analysis of animal manures in laboratory.