气相色谱法测定乳粉中1-油酸-2-棕榈酸-3-亚油酸甘油三酯含量的不确定度评定

Uncertainty Evaluation for the Determination of 1-Oleic Acid-2-Palmitic Acid-3-Linoleic Acid Triglyceride Content in Milk Powder by Gas Chromatography

评定气相色谱法测定乳粉中1-油酸-2-棕榈酸-3-亚油酸甘油三酯(1-oleic-2-palmitic-3-linoleic acid triglyceride,OPL)含量的不确定度。根据JJF1059.1—2012《测量不确定度评定与表示》和CNAS-GL006:2019《化学分析中不确定度的评估指南》等标准,建立不确定度模型,分析气相色谱法测定乳粉中OPL的不确定度来源,对主要影响不确定度的要素进行评定。结果表明:6份试样OPL测量结果的平均值为1.172 g/100 g,OPL含量测量结果的相对扩展不确定度u_(rel)为0.0236,提供约95%的包含概率;试样溶解并定容后的溶液质量浓度引入的标准不确定度是主要不确定度来源。

The measurement uncertainty was estimated for the determination of 1-oleic-2-palmitic-3-linoleic acid triglyceride(OPL)content in milk powder by gas chromatography(GC).According to the Measurement and Expression of Uncertainty in Measurement(JJF 1059.1—2012)and the Guidance on Quantifying Uncertainty in Chemical Analysis(CNAS-GL 006:2019),a mathematical model was established to analyze the sources of measurement uncertainty.The major factors affecting the measurement uncertainty were evaluated.Results showed that the average OPL content of six milk powder samples was measured to be 1.172 g/100 g.The relative expanded uncertainty(u_(rel))was 0.0236 with a coverage probability of approximately 95%.The standard uncertainty arising from sample preparation was the main source of uncertainty.