姜黄素分光光度法测定土壤有效硼的不确定度评定

Uncertainty evaluation of the available boron in soil with curcumin spetrophotonetry

测量不确定度是表征被测定值的分散性,并与测量结果相联系的参数。姜黄素分光光度法是测定土壤中有效硼主要方法之一,在其分析过程中操作步骤比较复杂,影响因素较多,但关于其不确定度的研究较少。评定了姜黄素分光光度法测定土壤中有效硼的不确定度。依照分析方法建立数学模型,并根据数学模型把不确定度分解为标准溶液不确定度、样品制备过程引入的不确定度、拟合标准曲线时所产生的不确定度、重复性实验引入的不确定度、试剂空白引入的不确定度和分析仪器引入的不确定度等,对影响测量结果的各个分量进行了分析评定,得出由标准溶液校准稀释过程引入的相对不确定度值是0.00535;样品制备过程引入的相对不确定度值是0.0370;拟合标准曲线时所产生的相对不确定度值是0.0124;重复性实验引入的相对不确定度值是0.00278;分析仪器引入的不确定度值是0.00150;样品的制备过程对测定结果的影响最大。以上因素是造成测定结果不确定度的主要分量。

Uncertainty is the parameter that attribute the dispersity of measured value and tied with the determinate value. Curcumin spectrophotonetry is one of the major method to determinate the available Boron in soil, with more complex operating procedure and more influencing factors. But the uncertainty research of this method is few. This article evaluated the uncertainty source of curcumin spectrophotonetry method. Established the mathematical model. According to this model, divided the total uncertainty to standard solution uncertainty, prepare procedure uncertainty, fitting regression line uncertainty, repeatability test uncertainty and analysis in- strument uncertainty. The component uncertainty that affect the result were evaluated, gain the value of standard solution uncertainty was 0.005 35, the value of prepare procedure uncertainty was 0.037 0, the value of fitting regression line uncertainty is 0.012 4, the value of repeatability test uncertainty was 0.002 78 and the value of analysis instrument uncertainty was 0.001 50. The prepare pro- cedure had the largest affect to the determination result. The above factors were major components to determination result uncertainty.