PDF(Pubmed)
Abstract：
Metal sub-microparticles (SMPs) and nanoparticles (NPs) presence in food is attributable to increasing pollution from the environment in raw materials and finished products. In the present study, a multifaceted analytical strategy based on Environmental Scanning Electron Microscopy and High-Angle Annular Dark-Field-Scanning Transmission Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (ESEM-EDX, HAADF-STEM-EDX) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was proposed for the detection and characterization of metal and metal-containing SMPs and NPs in durum wheat samples, covering a size measurement range from 1 nm to multiple µm. ESEM-EDX and ICP-MS techniques were applied for the assessment of SMP and NP contamination on the surface of wheat grains collected from seven geographical areas characterized by different natural and anthropic conditions, namely Italy, the USA, Australia, Slovakia, Mexico, Austria, and Russia. ICP-MS showed significant differences among the mean concentration levels of metals, with the USA and Italy having the highest level. ESEM-EDX analysis confirmed ICP-MS concentration measurements and measured the highest presence of particles < 0.8 µm in size in samples from Italy, followed by the USA. Less marked differences were observed when particles < 0.15 µm were considered. HAADF-STEM-EDX was applied to a selected number of samples for a preliminary assessment of internal contamination by metal SMPs and NPs, and to expand the measurable particle size range. The multifaceted approach provided similar results for Fe-containing SMPs and NPs. ICP-MS and ESEM-EDX also highlighted the presence of a significant abundance of Ti- and Al-containing particles, while for STEM-EDX, sample preparation artifacts complicated the interpretation. Finally, HAADF-STEM-EDX results provided relevant information about particles in the low nm range, since, by applying this technique, no particles smaller than 50 nm were observed in accordance with ESEM-EDX.
摘要：
食品中的金属亚微粒(SMP)和纳米颗粒(NPs)的存在归因于原材料和成品中来自环境的污染增加。在本研究中,基于环境扫描电子显微镜和大角度环形暗场扫描透射电子显微镜以及能量色散X射线光谱的多方面分析策略（ESEM-EDX，HAADF-STEM-EDX）和电感耦合等离子体质谱法（ICP-MS）被提出用于硬粒小麦样品中金属和含金属的SMPs和NPs的检测和表征，涵盖从1nm到多个µm的尺寸测量范围。ESEM-EDX和ICP-MS技术用于评估从七个具有不同自然和人为条件的地理区域收集的小麦籽粒表面的SMP和NP污染，即意大利,美国,澳大利亚,斯洛伐克,墨西哥,奥地利,和俄罗斯。ICP-MS显示金属的平均浓度水平之间存在显着差异，美国和意大利的水平最高。ESEM-EDX分析证实了ICP-MS浓度测量，并测量了来自意大利的样品中尺寸<0.8μm的颗粒的最高存在。其次是美国。当考虑颗粒<0.15μm时,观察到较少显著的差异。HAADF-STEM-EDX应用于选定数量的样品，以初步评估金属SMP和NP的内部污染，并扩大可测量的粒径范围。多方面的方法为含Fe的SMP和NP提供了类似的结果。ICP-MS和ESEM-EDX还强调了大量含Ti和Al的颗粒的存在，而对于STEM-EDX，样品制备工件使解释变得复杂。最后,HAADF-STEM-EDX结果提供了有关低nm范围内颗粒的相关信息，因为,通过应用这种技术，根据ESEM-EDX没有观察到小于50nm的颗粒。
