Sakkas V A, Giokas D L, Lambropoulou D A, Albanis T A
Laboratory of Industrial Chemistry, Department of Chemistry, University of Ioannina, Ioannina 45110, Greece.
J Chromatogr A. 2003 Oct 24;1016(2):211-22. doi: 10.1016/s0021-9673(03)01331-1.
The photochemical behavior of the sunscreen agent octyl-dimethyl-p-aminobenzoic acid (ODPABA) was studied in different aqueous solutions and under different conditions. ODPABA photolysis was performed under laboratory conditions using a xenon light source and under natural sunlight conditions in sea, swimming pool as well as in distilled water. The influence of dissolved organic matter (DOM) on the degradation kinetics was also studied in the presence of various concentrations of humic acids (HA). The phototransformation was shown to proceed via pseudo-first-order reaction in all cases and the reaction rates followed the order: distilled water > swimming pool water > seawater, depending mainly on the presence of dissolved organic matter that retarded the photolysis reaction. Kinetic experiments were monitored with HPLC/UV-DAD and the half-lives (t 1/2) varied between 1.6 and 39 h in simulated solar irradiation and between 27 and 39 h in natural sunlight conditions. The product distribution during illumination was strongly dependent on the constitution of the irradiated media. Irradiation of the aqueous ODPABA solutions gave rise to several transformation products that were isolated by means of solid-phase extraction (SPE) and identified using GC-MS techniques. These were formed mainly through dealkylation and hydroxylation reactions and were detected in all aqueous solutions investigated. In the case of swimming pool water some additional byproducts were isolated and were tentatively identified as chlorinated intermediates, formed by the subsequent chlorination of the parent molecule as well as other intermediates.
在不同水溶液和不同条件下研究了防晒剂辛基 - 二甲基 - 对氨基苯甲酸（ODPABA）的光化学行为。ODPABA的光解在实验室条件下使用氙灯光源进行，在自然阳光条件下于海水、游泳池水以及蒸馏水中进行。还研究了在各种浓度腐殖酸（HA）存在下溶解有机物（DOM）对降解动力学的影响。结果表明，在所有情况下光转化均通过准一级反应进行，反应速率遵循以下顺序：蒸馏水＞游泳池水＞海水，这主要取决于抑制光解反应的溶解有机物的存在。动力学实验通过HPLC/UV-DAD进行监测，在模拟太阳辐射下半衰期（t1/2）在1.6至39小时之间变化，在自然阳光条件下为27至39小时。光照期间的产物分布强烈依赖于被辐照介质的组成。ODPABA水溶液的辐照产生了几种转化产物，这些产物通过固相萃取（SPE）分离并使用GC-MS技术进行鉴定。它们主要通过脱烷基化和羟基化反应形成，并且在所有研究的水溶液中均被检测到。在游泳池水的情况下，分离出了一些额外的副产物，并初步鉴定为氯化中间体，这些中间体是由母体分子以及其他中间体的后续氯化形成的。
