The environmental accumulation and toxicity potential of metal oxide nanoparticles because of their increasing use in various commercial products have increased the interest in understanding the behavior of these materials in the aquatic environment. For example, zinc oxide (ZnO) is used in various industrial applications but exhibits partial solubility in aqueous media, therefore it has potential aquatoxic action. ZnO dissolves in water by releasing Zn²⁺ ions; thus, understanding the complexation behavior of these ions with water is crucial to be able to give a complete description of the fate of ZnO in aquatic environment. In this study, we propose application of a reliable and facile route based on the zincon analysis to further understand the Zn²⁺ complexation when ZnO is placed in aqueous media. To evaluate this, eight Zn²⁺ standards at a certain concentration were first prepared in the pH range between 7.0 and 10.0. Samples were analyzed via Inductive Coupled Plasma-Mass spectrometry (ICP-MS/MS) and the zincon analysis by monitoring their UV absorbance maximum at 620 nm. Analysis before and after centrifugation aided the investigation of the pH dependent complexation of Zn²⁺. In the centrifuged samples, the measured zinc ion fraction decreased, suggesting precipitation of zinc as zinc hydroxide (Zn(OH)₂(s)) in the solid form from the solution when the pH was increased from 7.0 to 10.0. However, there was no significant decrease in the non-centrifuged samples in the same pH range. These results show that the zincon analysis can be used to quantify both Zn²⁺_(aq) ions and Zn(OH)₂. Moreover, the zincon results were consistent with the results of ICP-MS/MS analyses. The centrifugation helps to sediment solid hydroxide particles enabling one to predict fraction of the ions and the hydroxides. Solid hydroxide precipitate was characterized by FTIR, XRD, SEM and EDX; and formation of orthorhombic Zn(OH)₂ phase was confirmed.

由于金属氧化物纳米颗粒在各种商业产品中的使用越来越多，因此其环境积累和潜在毒性增加了人们对了解这些材料在水生环境中行为的兴趣。例如，氧化锌 (ZnO) 用于各种工业应用，但在水性介质中表现出部分溶解性，因此它具有潜在的水毒作用。^{ZnO通过释放Zn 2+}离子溶于水；因此，了解这些离子与水的络合行为对于完整描述 ZnO 在水生环境中的命运至关重要。在这项研究中，我们建议应用基于锌分析的可靠且简便的途径来进一步了解 Zn ²⁺ZnO 置于水性介质中时的络合。为对此进行评估，首先在 7.0 至 10.0 的 pH 范围内制备了特定浓度的八种 Zn ^{2+标准品。}通过电感耦合等离子体质谱 (ICP-MS/MS) 分析样品，并通过监测其在 620 nm 处的最大紫外线吸光度进行锌分析。离心前后的分析有助于研究 Zn ²⁺的 pH 依赖性络合。在离心样品中，测得的锌离子分数降低，表明锌沉淀为氢氧化锌 (Zn(OH) ₂(s)) 当 pH 从 7.0 增加到 10.0 时从溶液中以固体形式存在。然而，在相同的 pH 范围内，未离心的样品没有显着降低。这些结果表明锌离子分析可用于量化 Zn ²⁺ _(aq)离子和 Zn(OH) ₂。此外，锌的结果与 ICP-MS/MS 分析的结果一致。离心有助于沉淀固体氢氧化物颗粒，使人们能够预测离子和氢氧化物的比例。固体氢氧化物沉淀物通过FTIR、XRD、SEM和EDX表征；并且证实了正交Zn(OH) ₂相的形成。