Departamento de Química, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil.
Rapid Commun Mass Spectrom. 2014 May 15;28(9):987-94. doi: 10.1002/rcm.6863.
Environmental bisphenol A (BPA) contamination is currently a matter of concern. This compound can disrupt the endocrine system by mimicking natural hormones and cause adverse effects on different organisms. In addition, it has been suggested that BPA can impair brain development, especially in fetuses and children. To efficiently remove BPA from contaminated water and wastewaters, several emerging technologies have been developed. Most are based on photodegradation. However, by-products resulting from the application of such methods have not been properly characterized.
The photodegradation of BPA was conducted using two different methods: photocatalysis (TiO2/UV-A and TiO2/UV-C systems) and direct photolysis (UV-A and UV-C radiation). The degradation process was continuously monitored to identify and observe the by-products formed under these conditions. Direct infusion electrospray ionization coupled to high-resolution mass spectrometry in negative ion mode [ESI(-)-HRMS] and liquid chromatography coupled to high-resolution mass spectrometry (HPLC/HRMS) were employed to monitor these by-products.
The results revealed that the TiO2/UV-C system was the most efficient in causing both BPA depletion and mineralization of the organic matter in solution. Moreover, accurate mass data allowed for the assignment of molecular formulae for seven by-products, many of them unprecedented, formed under these conditions. Thus, a route for the photodegradation of BPA in aqueous medium could be proposed based on these results. Finally, additional tests revealed that the by-products showed a higher toxicity against Artemia salina than the primary precursor.
All of these findings indicate that the identification of by-products arising from oxidative treatments is of primary importance because such compounds can be more hazardous than their precursors.
环境双酚 A（BPA）污染目前是一个值得关注的问题。这种化合物可以模拟天然激素干扰内分泌系统，对不同的生物体产生不良影响。此外，有研究表明，BPA 会损害大脑发育，尤其是在胎儿和儿童中。为了有效地从受污染的水和废水中去除 BPA，已经开发了几种新兴技术。大多数技术都是基于光降解的。然而，这些方法应用产生的副产物尚未得到适当的描述。
使用两种不同的方法进行 BPA 的光降解：光催化（TiO2/UV-A 和 TiO2/UV-C 系统）和直接光解（UV-A 和 UV-C 辐射）。连续监测降解过程，以识别和观察这些条件下形成的副产物。采用负离子模式下的直接注入电喷雾电离与高分辨率质谱联用（ESI(-)-HRMS）和高效液相色谱与高分辨率质谱联用（HPLC/HRMS）来监测这些副产物。
结果表明，TiO2/UV-C 系统是最有效的，既能使 BPA 耗尽，又能使溶液中有机物矿化。此外，精确的质量数据允许为在这些条件下形成的七种副产物分配分子公式，其中许多是前所未有的。因此，可以根据这些结果提出 BPA 在水介质中光降解的途径。最后，额外的测试表明，副产物对卤虫的毒性比原前驱物更高。
所有这些发现表明，识别氧化处理产生的副产物非常重要，因为这些化合物可能比其前体更具危害性。
