紫外可见分光光度法测定壁纸中甲醛的不确定度评定

采用紫外可见分光光度法测定壁纸中甲醛含量,对测定结果的不确定度进行评定。依据GB 18585–2001《室内装饰装修材料壁纸中有害物质限量》标准,对壁纸中甲醛含量的检测过程进行研究,系统地分析了整个检测过程不确定度的来源,包括重复测定、样品溶液的移取、标准工作溶液的配制、标准曲线的拟合和测定仪器等引入的不确定度。结合日常检测数据,首次采用欧洲标准化差值标准偏差的方法,对各不确定度分量进行评定。当壁纸中甲醛含量范围为0.54~28.47 mg/kg时,测定结果在95%置信区间时的相对扩展不确定度为0.035 2(k=2)。不确定度主要来源于样品移取过程中移液枪的使用、样品重复测定和标准曲线的拟合。

Uncertainty assessment of formaldehyde in wallpaper by UV-vis spectrophotometry

The concentration of formaldehyde in wallpaper was determined by UV-vis spectrophotometry and the uncertainty of measurement results was evaluated.According to the standard of GB 18585–2001"Indoor Decorating and Refurbishing Materials-Limit of Harmful Substances of Wallpapers",the detection process of formaldehyde content in wallpaper was studied,and the source of uncertainty of the whole detection process was systematically analyzed.Sources of uncertainty include repeat measurement,sample extracts,standard solution preparation,fitting curve,and measuring instruments.Combined with the daily test data,the European standard deviation method was used for the first time to quantify the uncertainty components.Ander the 95%confidence interval,when the formaldehyde concentration in the wallpaper was from 0.54 mg/kg to 28.47 mg/kg,the relative extended uncertainty was 0.0352(k=2).Uncertainty factors are mainly derived from the use of pipette during sample removal and the repeated measurement of sample and the fitting of standard curve.