高效液相色谱法测定食品用尼龙膜中己内酰胺迁移量不确定度的评定

Uncertainty evaluation of determination of caprolactam migration in nylon film for food by high performance liquid chromatography

目的评定高效液相色谱法(high performance liquid chromatography,HPLC)测定食品用尼龙膜中己内酰胺迁移量的不确定度。方法依据GB 31604.19-2016《食品安全国家标准食品接触材料及制品己内酰胺的测定和迁移量的测定》,采用高效液相色谱法分析研究食品用尼龙膜水基模拟液己内酰胺迁移量不确定度的大小。并建立数学模型,从测量结果的重复性、标准溶液配制、样品预处理、标准曲线拟合、空白溶液等方面,分析不确定度的来源,然后计算合成不确定度。结果测量结果的重复性、标准溶液配制、标准曲线拟合、样品预处理的相对不确定度分别为:0.00048、0.00916、0.01082、0.00289,合成不确定度为0.01448。样品中己内酰胺迁移量测量值的平均值为10.731 mg/L,其扩展不确定度为0.31 mg/L(k=2),则测量结果和不确定度的描述为(10.73±0.31)mg/L(k=2)。结论校准曲线拟合求浓度对己内酰胺迁移量的影响最大。日常检验中要保持仪器的稳定性、高灵敏度,并对仪器及时进行检定和期间核查。

Objective To evaluate the uncertainty in the determination of caprolactam migration in nylon film for food by high performance liquid chromatography （HPLC）. Method According to GB31604.19-2016 National food safety standards Food contact materials and products Determination of caprolactam and caprolactam migration, HPLC was used to analyze the uncertainty of the migration of caprolactam in nylon-based water-based simulation solutions for food. A mathematical model was established to analyze the sources of uncertainty from the repeatability of measurement results, preparation of standard solutions, sample pretreatment, standard curve fitting, and blank solutions. Then, the uncertainty of synthesis was calculated. Results The relative uncertainty of the repeatability of measurement results, standard solution preparation, standard curve fitting and sample pretreatment were 0.00048, 0.00916, 0.01082 and 0.00289, respectively, and the combined uncertainty was 0.01448. The average measurement value of caprolactam migration in the sample was 10.731 mg/L, the expanded uncertainty was 0.31 mg/L （k=-2）, and the result was expressed as （10.73±0.31） mg/L（k=2）. Conclusion Calibration curve fitting to find the concentration has the largest impact on the amount of caprolactam migration. In daily inspections, the stability and high sensitivity of the instrument must be maintained, and the instrument must be tested in a timely manner and checked during the period.