奈米技術的快速發展使得市場上奈米消費產品的數量顯著增加。其中，TiO2和ZnO奈米顆粒是常用於防曬劑和化妝品中的UV反射劑，但有許多奈米物質商品並未有明確的標示，且對安全風險評估的需求日益增加。此外，在產品使用期間奈米顆粒釋放到水環境(如廢水、河流和湖泊)中的宿命需要進行調查。
本研究的目的在於開發以單顆粒式感應耦合電漿質譜儀方法來直接分析市售防曬和化妝品中TiO2和ZnO的奈米顆粒大小、元素組成和濃度。選定的五個市售產品會以親/疏水的特性分類並使用不同的Triton X-100配方來分散樣品，由此方法分析得到的粒徑與穿透式電子顯微鏡的鑑定結果相當接近，其中四個產品所含的TiO2皆為奈米級顆粒，而ZnO則以大於100奈米的聚集體存於防曬產品中。其測得的五個樣品質量濃度則為感應耦合電漿質譜儀分析全消化樣品濃度的70-110%。另外，在台灣中部日月潭的一次大型游泳活動(約20,000名參與者)中調查了防曬奈米顆粒的釋放情形，發現在大部分的採樣位置(L1-2,L4-6)含鈦顆粒與總鈦濃度在泳渡期間皆有上升，而在泳渡三天後皆下降，顯示出釋放到湖水中的TiO2顆粒並不會停留很長的時間，其宿命可能為聚集並沉降至湖底。而總鋅濃度也在泳渡當天增加，但是含鋅顆粒卻是在泳渡之後，大部分位置(L1-2, L4-6)出現最高的顆粒濃度，顯示出從防曬劑中釋放的ZnO顆粒經歷了與TiO2截然不同的轉變過程。

Rapid developments in nanotechnology have led to a significant increase in the number of nano-enabled consumer products on the market. For example, TiO2 and ZnO are nanoparticles commonly used in sunscreen and cosmetic products as UV reflective agents. However, many products contain nanomaterials are not clearly labeled and there is an increasing requirement of risk assessment. Additionally, the release of nanoparticles into aqueous environments (e.g., wastewater, rivers, lakes) during product usage and their fate need to be investigated.
The objective in this study is to develop a direct method using spICP-MS to simultaneously quantify the size, elemental composition, and concentrations of nanosized TiO2 and ZnO in selected commercial sunscreen and cosmetic products. Five selected commercial products were classified by hydrophilic/hydrophobic properties and used different Triton X-100 formulations to disperse samples. The size of TiO2 and/or ZnO analyzed by spICP-MS is comparable to that by TEM imaging, which indicate that four of the five selected products studied in detail contain nanosized TiO2 particles, while ZnO particles as aggregation status (> 100 nm) exist in the original products. The mass concentrations of five selected products measured by spICP-MS represent 70-110% of those measured by traditional ICP-MS method with whole sample digestion. In addition, we examined the sunscreen nanoparticles release during a major swimming event (~20,000 participants) at the Sun Moon Lake in central Taiwan. We found that the number concentrations of particulate Ti and the mass concentration of Ti generally increase during the swimming event at most sampling (L1-2, L4-6) locations within the lake and then were reduced 3 days after, indicating that TiO2 nanoparticles do not remain suspended for a long time, and its fate may be aggregation and settling down the sediments. Similarly, Zn mass concentrations also increase during the event, but the Zn particle concentrations vary, showing the highest number concentrations of particulate Zn after the swimming event at most sampling (L1-2, L4-6) locations, which shows that the ZnO nanoparticles are very likely having a different transform process from TiO2 nanoparticles.

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