Chemistry and Biochemistry Program, Schmid College of Science, Chapman University, One University Drive, Orange, CA 92866, USA.
Chemistry and Biochemistry Program, Schmid College of Science, Chapman University, One University Drive, Orange, CA 92866, USA; Department of Chemistry, Austin College, 900 N. Grand Ave., Sherman, TX 75090, USA.
Mar Pollut Bull. 2024 Dec;209(Pt A):117073. doi: 10.1016/j.marpolbul.2024.117073. Epub 2024 Oct 10.
It is challenging to decouple typical protein-like chromophoric dissolved organic matter (CDOM) fluorophores from oil-related fluorophores in natural waters using standard steady-state fluorescence techniques. In the present work, time-resolved florescence spectroscopy was explored as a means of differentiating between these two types of fluorophores. Fluorescence lifetimes of oil products were measured as a function of excitation and emission wavelength in artificial seawater. A triexponential model gave τ = ~1-10 ns, τ = ~3-30 ns, and τ = ~0.2-2 ns. Time-resolved fluorescence amplitudes were dominated by τ (τ 55-65 %; τ 25-29 %; τ 11-16 %) and contributions to steady-state fluorescence were dominated by τ and τ. Lifetimes increased with decreasing λ. Fluorescence was quenched by halide ions, but ion concentrations in natural waters are insufficient for quenching to significantly change lifetimes. Heavier, denser oils had red-shifted emission and lower lifetimes. Results suggest that time-resolved spectroscopy can decouple oil and protein-like CDOM fluorophores at λ < 300 nm.
使用标准稳态荧光技术将典型的类蛋白色溶解性有机 matter (CDOM) 荧光团与天然水中的油相关荧光团分离具有挑战性。在本工作中，探索了时间分辨荧光光谱作为区分这两种荧光团的一种手段。在人工海水中，测量了油产物的荧光寿命作为激发和发射波长的函数。三指数模型给出 τ = ~1-10 ns，τ = ~3-30 ns，和 τ = ~0.2-2 ns。时间分辨荧光强度主要由 τ（τ 55-65%；τ 25-29%；τ 11-16%）决定，而对稳态荧光的贡献主要由 τ 和 τ 决定。寿命随 λ 的减小而增加。卤素离子会猝灭荧光，但天然水中的离子浓度不足以使猝灭显著改变寿命。更重、更密集的油具有红移发射和更低的寿命。结果表明，时间分辨光谱可以在 λ < 300nm 时分离油和类蛋白 CDOM 荧光团。
