The preparation and characterization of a matrix reference material for aflatoxin M₁ in milk powder is described. Milk powder samples containing aflatoxin M₁ were found in the screened natural milk samples. The preparation of matrix milk powder samples was developed through steps by vacuum concentration, spray-drying, cooling, mixing, weighing and packaging, and irradiation. This paper has developed a method for the determination of aflatoxin M₁ in milk powder by isotope dilution liquid chromatography–tandem mass spectrometry (ID-LC-MS/MS) with immunoaffinity extraction as the pretreatment method, which was validated and determined the content of aflatoxin M₁ in milk powder accurately. The homogeneity was studied by analyzing in triplicate for their aflatoxin M₁ contents by ID-LC-MS/MS using random sampling schemes. The short-term stability was evaluated at three different storage temperatures (4, 25 and 50 °C) for 0, 3, 5, 7, 14 days, the long-term stability study comprised of measurement after 0, 1, 3, 6, 9, 12 months after storage at 4 °C, and then, analyses were investigated by ID-LC-MS/MS. After the combination determination of 8 laboratories, the final quantity value and expanded uncertainty of matrix reference material of aflatoxin M₁in milk powder were: 0.49 ± 0.11 μg/kg, k = 2, P = 0.95, and the matrix reference material is homogenous and stable at 4 °C for at least 12 months, which can provide quality assurance for the later detection accuracy.

描述了奶粉中黄曲霉毒素M ₁的基质参考物质的制备和表征。在经筛选的天然牛奶样品中发现了含有黄曲霉毒素M _1的奶粉样品。基质奶粉样品的制备通过真空浓缩，喷雾干燥，冷却，混合，称重和包装以及辐照的步骤进行。本文建立了一种以免疫亲和萃取为预处理的同位素稀释液相色谱-串联质谱（ID-LC-MS / MS）测定奶粉中黄曲霉毒素M _1的方法，验证并确定了其中的含量。黄曲霉毒素M ₁准确地在奶粉中。通过使用随机采样方案通过ID-LC-MS / MS一式三份分析其黄曲霉毒素M ₁含量，研究了均质性。在三种不同的存储温度（4、25和50°C）下分别评估了0、3、5、7、14天的短期稳定性，长期稳定性研究包括在0、1、3、6之后的测量在4°C下储存后的第9、9、12个月，然后通过ID-LC-MS / MS进行分析。联合确定8个实验室后，奶粉中黄曲霉毒素M ₁的基质参考物质的最终量值和不确定度扩展为：0.49±0.11μg/ kg，k  = 2，P = 0.95，并且基质参考物质在4°C的温度下均质且稳定至少12个月，这可以为以后的检测准确性提供质量保证。