氨基酸分析仪测定玉米浆中17种游离氨基酸的不确定度评定

Uncertainties estimation for determination of 17 free amino acidsin corn steep liquor by amino acid analyzer

摘要: 依据GB/T 18246-2000,应用氨基酸分析仪测定了玉米浆中17种游离氨基酸含量。在此基础上,应用"bottom-up"方法对分析过程中可能引入测量不确定度的6个因素包括重复性、称量、定容、样品稀释、标准溶液配制和摩尔质量进行了评定和计算。包含因子k=2时,所有氨基酸的扩展不确定度范围为0.01%⁰.04%。以谷氨酸为例,计算了各不确定度分量在相对合成不确定度中的贡献,结果表明,标准溶液配制和重复性在合成不确定度中的贡献最大。

Abstract: 17 free amino acids, in corn steep liquor were detected by amino acid analyzer according to GB /T 18246-2000. The “bottom-up ” approach was used to estimate the sources of uncertainty, such as repeatability, weighing of the sample, sample volume, sample dilution, stock solution and molar mass. The range of expanded uncertainties for all of the free amino acids was 0.01% to 0.04%. Taking glutamic acid as an example, the percentage contribution of each source to the relative combined uncertainties was calculated.The data of glutamic acid indicated that the major contributions to the uncertainty budget originating from the stock solution and repeatability.