目的 建立可同时测定保健品中烟酰胺腺嘌呤二核苷酸(nicotinamide adenine dinucleotide,NAD+)及其前体化合物含量的核磁共振波谱法.方法 采用核磁共振波谱技术,优化检测条件后,开发了标准曲线法和定量核磁共振法(quantitative nuclear magnetic resonance,qNMR)两种定量检测方法,用于测定保健品中两种形式的NAD及其 4 种前体化合物.结果 确定了各目标化合物的特征峰.对于标准曲线法,6 种目标化合物的线性关系良好(r≥0.9999),除烟酰胺(nicotinamide,NAM)的定量限为0.5 mmol/L外,其他5种目标化合物的定量限均为 0.2 mmol/L.考察了两种具有代表性的 NAD+前体化合物的日间和日内重现性,烟酰胺单核苷酸(nicotinamide mononucleotide,NMN)和NAM的日间重现性分别为 0.21%和 0.37%,日内重现性分别为 1.03%和1.44%.用标准曲线法和qNMR两种方法分别对收集的10个NAD+补充剂保健品进行检测,误差合理(<5%).结论 建立的核磁共振方法具有良好的可靠性和灵敏度,可用于保健品中 NAD+及其前体化合物的生产控制和市场监管.
Objective To develop and establish nuclear magnetic resonance-based method which could simultaneously determine the content of nicotinamide adenine dinucleotide(NAD+)and its precursors in food supplement products.Methods Based on nuclear magnetic resonance technique,after the selection of optimal acquisition conditions,2 kinds of quantitative methods,calibration curve and quantitative nuclear magnetic resonance(qNMR),were established to determine two forms of NAD and its 4 kinds of precursors in food supplements.Results The characteristic peaks of each target were selected.The linearity of calibration curve method of 6 kinds of investigated compounds was good(r≥0.9999).The limits of quantitation were 0.5 mmol/L for nicotinamide(NAM)or 0.2 mmol/L for 5 kinds of other target compounds.The inter-day and intra-day reproducibility of two representative NAD+ precursors were also studied.The inter-day reproducibility was 0.21%for nicotinamide mononucleotide(NMN)and 0.37%for NAM respectively,and the intra-day reproducibility were 1.03%and 1.44%,respectively.Ten commercial samples of NAD+ supplementary products collected were tested by both calibration curve and qNMR methods with reasonable error(less than 5%).Conclusion The proposed nuclear magnetic resonance methods have good reliability and sensitivity and could be applied in production control and administrative regulation for food supplements of NAD+ and its precursors.