Division for Food Technology, National Food Institute, Technical University of Denmark, Kemitorvet 201, Kgs. Lyngby DK-2800, Denmark.
J Agric Food Chem. 2021 Sep 1;69(34):9979-9990. doi: 10.1021/acs.jafc.0c07363. Epub 2021 Aug 20.
In this work, we show the potential of single-particle inductively coupled plasma-mass spectrometry (spICP-MS) as a screening technique for detection of inorganic nanoparticles (NPs) that are expected to be present in food. We demonstrate that the spICP-MS/MS method in combination with collision/reaction cell gases and microsecond dwell times offers sensitive and interference-free detection of NPs. We present the steps that have to be considered to correctly assess the presence of NPs in food, for example, setting a suitable threshold for discriminating particle events from the baseline and analyzing a sufficient number of blank samples to minimize false-positive results. We applied the proposed screening approach to the sequential detection of NPs containing 8 selected elements that could be potentially present in 13 different food products. The highest mass concentrations of NPs (in the mg/g range) were found in the samples with food additives which are known to contain a fraction of NPs. The presence of (nano)particles in some of the investigated food samples was also confirmed by scanning electron microscopy analysis. Moreover, for the example of Al-containing NPs in Chinese noodles, we demonstrate that identification of the source of NPs with an unknown composition can be challenging when using only spICP-MS as particle mass concentration and size distribution can only be estimated by assuming a certain particle composition/shape. Other complementary techniques for particle characterization, such as electron microscopy in combination with elemental analysis, are therefore required.
在这项工作中，我们展示了单颗粒电感耦合等离子体质谱（spICP-MS）作为一种筛选技术，用于检测预计存在于食品中的无机纳米颗粒（NPs）。我们证明，结合碰撞/反应池气体和微秒停留时间的 spICP-MS/MS 方法提供了对 NPs 的敏感且无干扰的检测。我们提出了正确评估食品中 NPs 存在的步骤，例如，设定适当的阈值来区分粒子事件与基线，以及分析足够数量的空白样品以最小化假阳性结果。我们将所提出的筛选方法应用于顺序检测含有 8 种选定元素的 NPs，这些元素可能存在于 13 种不同的食品中。在含有食品添加剂的样品中发现了 NPs 的最高质量浓度（在 mg/g 范围内），这些添加剂已知含有一定比例的 NPs。在一些研究的食品样品中也通过扫描电子显微镜分析证实了（纳米）颗粒的存在。此外，对于中国面条中含 Al 的 NPs 示例，我们证明了当仅使用 spICP-MS 时，由于只能通过假设一定的颗粒组成/形状来估计颗粒质量浓度和粒径分布，因此识别具有未知成分的 NPs 的来源可能具有挑战性。因此，需要其他互补的颗粒表征技术，例如与元素分析相结合的电子显微镜。
