Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Zografou, Athens 15771, Greece.
Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Zografou, Athens 15771, Greece.
Sci Total Environ. 2016 Jul 1;557-558:170-82. doi: 10.1016/j.scitotenv.2016.03.026. Epub 2016 Mar 18.
This study focuses on the effect of experimental parameters on the removal of ranitidine (RAN) during ozonation and the identification of the formed transformation products (TPs). The influence of pH value, the initial concentrations, the inorganic and the organic matter on RAN's removal were evaluated. Results indicated high reactivity of RAN with molecular aqueous ozone. Initial ozone concentration and pH were proven the major process parameters. Alkaline pH values promoted degradation and overall mineralization. Dissolved organic matter reacts competitively to RAN with the oxidants (ozone and/or radicals), influencing the target compound's removal. The presence of inorganic ions in the matrix did not seem to affect RAN ozonation. A total of eleven TPs were identified and structurally elucidated, with the complementary use of both Reversed Phase (RP) and Hydrophilic Interaction Liquid Chromatography (HILIC) quadrupole time of flight tandem mass spectrometry (Q-ToF-MS/MS). Most of the TPs (TP-304, TP-315b, TP-299b, TP-333, TP-283) were generated by the attack of ozone at the double bond or the adjacent secondary amine, with the abstraction of NO2 moiety, forming TPs with an aldehyde group and an imine bond. Oxidized derivatives with a carboxylic group (TP-315a, TP-331a, TP-331b, TP-299a) were also formed. RAN S-oxide was identified as an ozonation TP (TP-330) and its structure was confirmed through the analysis of a reference standard. TP-214 was also produced during ozonation, through the CN bond rupture adjacent to the NO2 moiety. HILIC was used complementary to RP, either for the separation and identification of TPs with isomeric structures that may have been co-eluted in RPLC or for the detection of new TPs that were not eluted in the RP chromatographic system. Retention time prediction was used as a supporting tool for the identification of TPs and results were in accordance with the experimental ones in both RP and HILIC.
本研究聚焦于实验参数对臭氧化去除雷尼替丁（RAN）的影响以及所形成转化产物（TPs）的鉴定。评估了 pH 值、初始浓度、无机和有机物对 RAN 去除的影响。结果表明 RAN 与分子态臭氧具有高反应性。初始臭氧浓度和 pH 值被证明是主要的工艺参数。碱性 pH 值促进了降解和整体矿化。溶解的有机物与氧化剂（臭氧和/或自由基）竞争反应，影响目标化合物的去除。基质中无机离子的存在似乎并不影响 RAN 的臭氧化。共鉴定并结构解析了 11 种 TPs，使用反相（RP）和亲水相互作用液相色谱（HILIC）四极杆飞行时间串联质谱（Q-ToF-MS/MS）的互补方法。大多数 TPs（TP-304、TP-315b、TP-299b、TP-333、TP-283）是由臭氧攻击双键或相邻的仲胺生成的，同时还伴随着 NO2 部分的抽提，形成具有醛基和亚胺键的 TPs。还形成了具有羧基的氧化衍生物（TP-315a、TP-331a、TP-331b、TP-299a）。RAN S-氧化物被鉴定为臭氧化 TPs（TP-330），其结构通过分析参考标准得到确认。TP-214 也是在臭氧化过程中产生的，通过与 NO2 部分相邻的 CN 键断裂生成。HILIC 与 RP 互补使用，用于分离和鉴定可能在 RPLC 中共同洗脱的具有同分异构结构的 TPs 或用于检测在 RP 色谱系统中未洗脱的新 TPs。保留时间预测被用作鉴定 TPs 的辅助工具，结果与 RP 和 HILIC 中的实验结果一致。
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