复混肥料中有效磷含量不确定度的评定

Evaluation on the Uncertainty of Available Phosphorous Content in Compound Fertilizer

[目的]建立复混肥料中有效磷含量不确定度的评定方法。[方法]用磷钼酸喹啉重量法测定有效磷含量,通过建立数学模型分析测量结果的不确定度。[结果]磷钼酸喹啉沉淀和试样质量的不确定度均来自天平的分辨力、精确度、鉴定证书上天平的最大允差,容量瓶引入的不确定度来自250 ml容量瓶本身的允许误差、稀释溶液时将体积增加到容量瓶刻度的操作和试验温度与容量瓶校准时温度的差异,吸量管引入的不确定度来自于吸量管本身的允许误差、吸取溶液时将体积增加到吸取刻度时的操作和试验温度与吸量管校准时温度的差异。最后计算出测量结果的不确定度为16.3%±0.3%。[结论]该试验为复合肥料质量评定提供了科学依据和方法支持。

[Objective] The purpose was to establish an evaluation method for the uncertainty of available phosphorous（P） content in compound fertilizer.[Method] The available P content was measured by quinoline phosphomolybdate gravimetric method and the uncertainty of measured results was analyzed through establishing mathematic model.[Result] It could be concluded through analyzing the model that both the mass uncertainties of quinoline phosphomolybdate precipitates and tested samples were from the resolving power and precision of balance and its maximum tolerance in assay certificate;the uncertainty brought in by volumetric flask was from the permissible error of 250 ml volumetric flask,the operation of increasing the volume to scale of volumetric flask while diluting solution and the difference between experimental temperature and the temperature at the time when the volumetric flask was calibrated;the uncertainty brought in by pipette was from the permissible error of itself,the operation of increasing the volume to intake scale while taking solution and the difference between experimental temperature and the temperature at the time when the pipette was calibrated.At last,the uncertainty of measured results was calculated to be 16.3%±0.3%.[Conclusion] This experiment supplied scientific basis and methodological support for the quality evaluation of compound fertilizers.