石墨炉原子吸收光谱法测定皂树皮提取物中铅的不确定度评定

摘要

Object:To study and assess the uncertainty of Lead in quillaia extract by graphite furnace atomic absorption spectrometer (GFAAS).Method:The Lead contents in two quillaia extract samples (X1 and X2) were determinate by GFAAS and the uncertainties were calculated by sample weight,volume,standard solution preparation,standard curveinthe mathematical model.Result:The Lead content in sample X1 was 1.28 mg/kg and the expanded uncertainty was 0.090 mg/kg (k=2).The Lead content in sample X2 was 3.90 mg/kg and the expanded uncertainty was 0.250 mg/kg (k=2).Conclusion:The recovery,variability of the blank,lead content in digestive solution and duplicability were four major factors in calculating the uncertainty.The reasonable assessment of measuring uncertainty could be made for determination of Lead in solid samples by GFAAS through establishing a mathematical model.%目的:探讨石墨炉原子吸收光谱法测定皂树皮提取物中铅不确定度的评定方法.方法:用原子吸收光谱仪测定皂树皮提取物样品中铅含量,根据该分析过程的测量数学模型从样品称量、样品定容、标准溶液配制、标准曲线测定、样品和空白测定等方面进行测量不确定度的计算.结果:样品X1铅含量为1.28 mg/kg,扩展不确定度为0.090mg/kg (k=2);样品X2铅含量为3.90 mg/kg,扩展不确定度为0.250mg/kg (k=2).结论:测量过程中的不确定度主要来源于方法的回收率、样品空白变动性、消化液中铅浓度和重复性.通过建立测量数学模型,可对石墨炉原子吸收光谱法测定固体样品中铅测量的不确定度进行合理的评定.