Methodology for the accurate determination of number concentration of inorganic nanoparticles (NP) by single particle inductively coupled plasma mass spectrometry (spICP-MS) using the novel dynamic mass flow (DMF) approach is systematically described. Using this method the determination of transport efficiency (TE) is achieved without the need for a reference nanomaterial. The impact of key parameters on the accuracy and uncertainty of the number concentration data obtained with this approach was evaluated. In particular the number of detected NP in the time scan is the major contributing factor to the overall measurement uncertainty. For Au NP of spherical shape with number based concentration in the range of 4.0 × 10¹² to 2.0 × 10¹⁴ kg⁻¹ (depending on the particle size) a relative expanded uncertainty (k = 2) of less than 10% was achieved. This reference methodology was also evaluated for the accurate determination of number concentration of more complex NP namely triethanolamine (TEA)-stabilised TiO₂ NP, for which like-for-like NP reference materials are not available. Using a sample mass flow of 0.3578 g min⁻¹ (with an associated uncertainty of 0.0002 g min⁻¹, k = 1) the average transport efficiencies for Au NP (in trisodium citrate) and TiO₂ NP (in TEA/NaOH) were very similar (7.57 ± 0.13% and 7.77 ± 0.22%, k = 1, respectively). Finally the number concentration values for both NP types agreed well with those obtained using particle tracking analysis (PTA), providing evidence for the good agreement between mass-based TE of the sample and NP-based TE with the newly proposed method.

中文翻译：

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使用动态质量流方法使用spICP-MS准确测定无机纳米颗粒的数量浓度

系统地介绍了使用新型动态质量流（DMF）方法通过单颗粒电感耦合等离子体质谱法（spICP-MS）准确确定无机纳米颗粒（NP）数浓度的方法。使用这种方法，无需参考纳米材料即可确定传输效率（TE）。评估了关键参数对通过这种方法获得的数字浓度数据的准确性和不确定性的影响。特别是在时间扫描中检测到的NP数量是导致整体测量不确定性的主要因素。对于球形的Au NP，其基于数量的浓度范围为4.0×10 ¹²至2.0×10 ¹⁴ kg ^-1（取决于粒径），相对膨胀不确定度（k = 2）小于10％。还对该参考方法进行了评估，以准确测定更复杂的NP的浓度，即三乙醇胺（TEA）稳定的TiO ₂ NP，但尚无类似的NP参考材料。使用0.3578 g min ^-1的样品质​​量流量（相关不确定性为0.0002 g min ^-1，k = 1），Au NP（在柠檬酸三钠中）和TiO ₂ NP（在TEA / NaOH中）的平均传输效率为非常相似（7.57±0.13％和7.77±0.22％，k= 1）。最后，两种NP类型的数字浓度值与使用粒子跟踪分析（PTA）获得的数字浓度值非常吻合，从而为使用新提出的方法的样品基于质量的TE与基于NP的TE之间的良好一致性提供了证据。