缓释尿素中硝化抑制剂DMPP的气相色谱法测定

Determination of nitrification inhibitor DMPP in slow-release urea by gas chromatography

建立了一种检测缓释尿素中吡唑类硝化抑制剂DMPP的气相色谱法。DMPP在尿素水溶液中可定量转化为DMP,从5种有机溶剂中选择氯仿作为DMP的萃取剂,并采用加入KCl盐析的方法将萃取率从96.1%提高到99.5%。本文采用吡啶作为内标物,通过DB-1701气相色谱柱,氢火焰离子化检测器（FID）定量检测氯仿溶液萃取相中的DMP。萃取率为98.8%～100.4%;添加回收率为98.1%～99.5%;RSD为0.84%～1.6%。应用本法测定自制缓释尿素中DMPP质量分数为0.44%。

A new method is developed to determine nitrification inhibitor DMPP in slow-release urea by gas chromatography based on the transformation of DMPP to DMP in urea solution. Chloroform was found to be the best extractant in five organic solvents tested. The efficiency of extraction could increase from 96.1% to 99.5 % by the addition of KCl for salting-out. Pyridine was applied as the internal standard and a DB-1701 colume and a flame-ionization detector （FID） were used for the GC determination of DMP. The results showed that the extraction efficiencies were from 98.8% to 100.4%, the recoveries were from 98.1% to 99.5%, and the coefficient of variation was from 0.84% to 1.55%, respecticely. The DMPP content of slow-release urea determined by using this method was 0.44%.