A hydrofluoric acid-free method to dissolve and quantify silica nanoparticles in aqueous and solid matrices
A hydrofluoric acid-free method to dissolve and quantify silica nanoparticles in aqueous and solid matrices
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DOI：
10.1038/s41598-019-44128-z
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发表时间：
2019-05-28
影响因子：
4.6
通讯作者：
Schwab, Fabienne
中科院分区：
文献类型：
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作者：
Bossert, David;Urban, Dominic A.;Schwab, Fabienne
随着合成无定形二氧化硅纳米材料（SiO2-NPs）商业用途的增加，其对环境和人类健康的影响仍未得到详细探讨。对于二氧化硅- np的命运和危害研究来说，一个经常无法克服的障碍是对固体颗粒二氧化硅的分析，这涉及到有毒和腐蚀性的氢氟酸（HF）。因此，我们开发并验证了一套简单的无氢氟酸样品制备方法，用于定量无定形SiO2微粒子和纳米粒子。为了避免HF，我们在室温下或在氢氧化钾微波照射下通过碱催化水解溶解SiO2-NPs，用OH-取代稳定的氟离子，并利用正硅酸单体在强碱ph下的稳定性。电感耦合等离子体光学发射光谱（ICP-OES）或比色法用于定量硅。在pH值为bbb12时，胶体SiO2- nps的有效溶解和量化的最低KOH: SiO2摩尔比为1.2。气相SiO2- nps （Aerosil (R)）或含有SiO2- nps的食品级SiO2 （E551）在较高的KOH: SiO2比bb0 8000下可降解。因此，基于KOH的无氢氟酸SiO2-NP消化方案是一种有效的（回收率为80.84%）、危害小且易于实施的替代方法。
As the commercial use of synthetic amorphous silica nanomaterials (SiO2-NPs) increases, their effects on the environment and human health have still not been explored in detail. An often-insurmountable obstacle for SiO2-NP fate and hazard research is the challenging analytics of solid particulate silica species, which involves toxic and corrosive hydrofluoric acid (HF). We therefore developed and validated a set of simple hydrofluoric acid-free sample preparation methods for the quantification of amorphous SiO2 micro- and nanoparticles. To circumvent HF, we dissolved the SiO2-NPs by base-catalyzed hydrolysis at room temperature or under microwave irradiation using potassium hydroxide, replacing the stabilizing fluoride ions with OH-, and exploiting the stability of the orthosilicic acid monomer under a strongly basic pH. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) or a colorimetric assay served to quantify silicon. The lowest KOH: SiO2 molar ratio to effectively dissolve and quantify SiO2-NPs was 1.2 for colloidal Stober SiO2-NPs at a pH >12. Fumed SiO2-NPs (Aerosil (R)) or food grade SiO2 (E551) containing SiO2-NPs were degradable at higher KOH: SiO2 ratios >8000. Thus, hydrofluoric acid-free SiO2-NP digestion protocols based on KOH present an effective (recoveries of >84%), less hazardous, and easy to implement alternative to current methods.