Hennemann Artur L, Nogueira Helton P, Ramos Miguel D, Correra Thiago C, Hennemann Bruno L, Araki Koiti
Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, SP, Brazil.
ACS Omega. 2024 Nov 18;9(48):47831-47841. doi: 10.1021/acsomega.4c08770. eCollection 2024 Dec 3.
Amorphous 3 nm large ultrasmall (TiO) and 7 nm large anatase (TiO) nanoparticles (NPs) were successfully prepared and characterized by TEM, FTIR, DRX, UV-vis, and DLS techniques. The MALDI-TOF/MS was shown to be effective in assessing the surface chemistry but fragmentation processes precluded its use for evaluation of particle size distribution. In fact, the laser causes the fragmentation not only of amorphous TiO NPs but also of the material subjected to heat treatment and crystallization at 450 °C for 4 h upon interaction with the DHB matrix and TFA ionizing agent. No significant difference could be observed in the spectrum by varying the particle size, indicating the high stability of the TiO dimer and its low aggregates in the gaseous phase. In short, MALDI-TOF/MS is effective for the direct analysis of nanoparticle surfaces, especially the interaction of functionalizing molecular species with the inorganic components, which in combination with the other techniques demonstrated to be ideal for the detailed characterization of nanomaterials.
成功制备了非晶态的3纳米大的超小（TiO）和7纳米大的锐钛矿（TiO）纳米颗粒（NPs），并通过透射电子显微镜（TEM）、傅里叶变换红外光谱（FTIR）、X射线衍射（DRX）、紫外可见光谱（UV-vis）和动态光散射（DLS）技术对其进行了表征。基质辅助激光解吸电离飞行时间质谱（MALDI-TOF/MS）被证明在评估表面化学方面是有效的，但碎片化过程使其无法用于评估粒径分布。事实上，激光不仅会导致非晶态TiO NPs碎片化，还会导致与2,5-二羟基苯甲酸（DHB）基质和三氟乙酸（TFA）电离剂相互作用时在450℃下热处理4小时的材料发生碎片化。通过改变粒径，在光谱中未观察到显著差异，这表明TiO二聚体在气相中的高稳定性及其低聚集体。简而言之，MALDI-TOF/MS对于纳米颗粒表面的直接分析是有效的，特别是功能化分子物种与无机成分的相互作用，与其他技术相结合，被证明是纳米材料详细表征的理想方法。
