高效液相色谱法测定奶粉质控样品中三聚氰胺的含量及其不确定度分析

目的 采用高效液相色谱法(high-performance liquid chromatography, HPLC)测定奶粉质控样品中三聚氰胺的含量并进行不确定度的分析。方法 以GB/T 22388-2008 《原料乳与乳制品中三聚氰胺检测方法》第一法为基础, 在实验过程中进行2次提取改良前处理方法测定奶粉质控样品中三聚氰胺含量, 建立数学模型, 分析实验过程中所产生的不确定度的来源, 并进行不确定度的评定分析。结果 通过改进前处理方法, 回收率提高到80%~90%, 稳定性相对标准偏差为1.96%。当k=2(95%置信度)时, 奶粉质控样品中三聚氰胺含量为(0.61±0.021) mg/kg, 质控样品的测试结果为满意。结论 在实验操作过程中, 实验人员应熟练掌握分析技能, 严格按照操作规程进行检测, 以减少检测结果的不确定度, 从而保证检测结果的可靠性。

Uncertainty evaluation for the determination of melamine residues in milk powder quality control samples by high-performance liquid chromatography

Objective Determination of melamine in milk powder quality control samples by high-performance liquid chromatography (HPLC) and analysis of uncertainty. Methods Based on the first method of GB/T 22388-2008 Detection Method of Melamine in Raw Milk and Dairy Products, the content of melamine in quality control samples of milk powder was determined by the pre-treatment method of twice extraction during the experiment. A mathematical model was established to analyze the sources of uncertainty in the experimental process and to evaluate and analyze the uncertainty. Results By improving the pretreatment method, the recovery rate increased to 80%-90%, and the stability of the relative standard deviation was 1.96%. The results showed that when k=2 (95% confidence), the content of melamine in milk powder quality control sample was (0.61 ±0.021) mg/kg, and the test results were satisfactory. Conclusion In the process of experimental operation, the laboratory personnel should be proficient in the analysis skills, and test in strict accordance with the operating procedures to reduce the uncertainty of the test results, so as to ensure the reliability of the test results.