Elsheref Mohamed, Cao Xian, Tarr Matthew A
Department of Chemistry, University of New Orleans, USA.
Department of Chemistry, University of New Orleans, USA.
J Hazard Mater. 2024 Jul 5;472:134427. doi: 10.1016/j.jhazmat.2024.134427. Epub 2024 Apr 26.
Aldehyde and ketone oxocarboxylic acid photoproducts were semi-quantitated in the aqueous phase after subjecting Macondo (MC252) crude oil-seawater systems to simulated solar irradiation. Electrospray ionization tandem mass spectrometry (ESI-MS/MS) was applied after derivatizing the samples with 2,4-dinitrophenylhydrazine (DNPH). Oil-seawater was irradiated at 27.0 °C using a solar simulator for 1 to 18 h. Following irradiation, the aqueous phase was treated with DNPH to generate aldehyde-DNPH and ketone-DNPH derivatives. Solid-phase extraction enriched the samples before analyzing them using (-) ESI-MS/MS. Precursor and product ion spectra were used to select carboxylic acid-containing aldehydes and ketones and provide semi-quantitation using surrogate standards and an internal standard. Loss of m/z 44 (CO) in the product ion spectra further confirmed the carboxylic acid character. Near-linear increases in photoproduct concentration in the aqueous phase were observed over the 18 h irradiation period. Among the aldehyde and ketone oxocarboxylic acid photoproducts studied, photoproduction rates ranged from 0.6 - 69 µmol/h·m of oil surface. Despite some fluctuations, a general trend of lower production rate with higher molecular weight was observed. These results demonstrate the near-linear dependence of photoproduction on irradiance and provide ranges of rates that can be applied to modeling aldehyde and ketone oxocarboxylic acid photoproduction in ocean spills. STATEMENT OF ENVIRONMENTAL IMPACT: Crude oil on seawater degrades when exposed to sunlight. Oxygenated molecules are produced, including carboxylic acid-containing aldehydes and ketones. The formation of these photoproducts from oil films behaves linearly with solar exposure time. These photoproducts are more soluble than the original oil molecules, allowing them to have increased bioavailability and potentially increased toxicity. The rate of formation of these species when oil is exposed to sunlight determines their environmental impact.
在对马孔多（MC252）原油 - 海水体系进行模拟太阳辐射后，对水相中醛和酮氧代羧酸光产物进行了半定量分析。在用2,4 - 二硝基苯肼（DNPH）对样品进行衍生化处理后，应用电喷雾电离串联质谱（ESI - MS/MS）进行分析。使用太阳模拟器在27.0°C下对油 - 海水进行1至18小时的辐射。辐射后，水相用DNPH处理以生成醛 - DNPH和酮 - DNPH衍生物。在使用（ - ）ESI - MS/MS分析样品之前，固相萃取对样品进行了富集。前体离子和产物离子光谱用于选择含羧酸的醛和酮，并使用替代标准物和内标进行半定量。产物离子光谱中m/z 44（CO）的丢失进一步证实了羧酸的特性。在18小时的辐射期内，观察到水相中光产物浓度呈近线性增加。在所研究的醛和酮氧代羧酸光产物中，光生成速率范围为0.6 - 69 μmol/h·m油表面。尽管存在一些波动，但观察到分子量越高生成速率越低的总体趋势。这些结果证明了光生成对辐照度的近线性依赖性，并提供了可应用于模拟海洋溢油中醛和酮氧代羧酸光生成的速率范围。环境影响声明：海水中的原油在暴露于阳光时会降解。会产生含氧分子，包括含羧酸的醛和酮。油膜中这些光产物的形成与阳光照射时间呈线性关系。这些光产物比原始油分子更易溶，使其具有更高的生物利用度并可能增加毒性。油暴露于阳光时这些物质的形成速率决定了它们的环境影响。
