Group of Analytical Spectroscopy and Sensors (GEAS), Institute of Environmental Sciences (IUCA), University of Zaragoza, Pedro Cerbuna, 12, 50009, Zaragoza, Spain.
Trace Element, Spectroscopy and Speciation Group (GETEE), Strategic Grouping in Materials (AEMAT), Department of Analytical Chemistry, Nutrition and Bromatology. Faculty of Chemistry. Universidad de Santiago de Compostela, Avenida Das Ciencias, S/n, 15782, Santiago de Compostela, Spain.
Anal Chim Acta. 2020 Jul 25;1122:20-30. doi: 10.1016/j.aca.2020.04.080. Epub 2020 May 5.
A procedure for the size characterization and quantification of titanium dioxide (TiO) nano- and microparticles by Asymmetric Flow Field-Flow Fractionation (AF4) coupled to Dynamic Light Scattering (DLS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is described. Different strategies for size characterization with size standards and the use of the DLS signal for the estimation of hydrodynamic diameters are evaluated. The procedure has been applied to the characterization of TiO nanoparticles in photocatalytic products and crab sticks (surimis), where TiO is present as E171 food additive. Sizes in the range of 50-90 nm and 160-170 nm were estimated in the different photocatalytic products by AF4-DLS, in good agreement with the sizes predicted by calibration versus SiO and polystyrene standards. In surimis, sizes between 140 and 350 nm were estimated by AF4-DLS, similar to those reported in literature for E171 additive. These results were also compared to those obtained by single particle ICP-MS, which allowed the detection of a nano-sized fraction of TiO present in the four surimis analyzed. Titanium contents in one of the photocatalytic products determined by AF4-ICP-MS was 16.86 ± 2.54 mg g, whereas the alkaline extraction followed by AF4-ICP-MS allowed the determination of TiO content in four surimis at concentration levels in the range of the μg g (from 3.14 ± 0.10 to 14.55 ± 1.46 μg Ti g), with channel recoveries above 85% in all cases. The method has been validated by comparison with the Ti content determined by ICP-OES after microwaved assisted acid digestion of all the samples. The methodology proposed allows the complete quantification of the (nano)particulate forms of titanium in complex matrices together with their size characterization.
一种通过不对称流场流分离（AF4）与动态光散射（DLS）和电感耦合等离子体质谱（ICP-MS）联用对二氧化钛（TiO ）纳米和微米颗粒进行尺寸表征和定量的方法。评估了使用标准品进行尺寸表征和使用 DLS 信号估计流体力学直径的不同策略。该方法已应用于光催化产品和蟹棒（surimi）中 TiO 纳米颗粒的表征，其中 TiO 作为 E171 食品添加剂存在。通过 AF4-DLS 在不同的光催化产品中估计出 50-90nm 和 160-170nm 范围内的粒径，与用 SiO 和聚苯乙烯标准品校准预测的粒径非常吻合。在 surimi 中，通过 AF4-DLS 估计出 140-350nm 的粒径，与文献中报道的 E171 添加剂粒径相似。这些结果还与单颗粒 ICP-MS 获得的结果进行了比较，后者可以检测到四种分析的 surimi 中存在的纳米级 TiO 分数。通过 AF4-ICP-MS 测定的一种光催化产品中的钛含量为 16.86±2.54mg g，而碱性提取后再通过 AF4-ICP-MS 可在 μg g 浓度范围内测定四种 surimi 中的 TiO 含量（范围为 3.14±0.10 至 14.55±1.46μg Ti g），所有情况下通道回收率均高于 85%。该方法通过与所有样品微波辅助酸消解后用 ICP-OES 测定的 Ti 含量进行比较得到验证。所提出的方法允许对复杂基质中（纳米）颗粒形式的钛进行完全定量，同时还可以对其尺寸进行表征。
