Study on the Fluorescence Characteristic of Phenanthrenes and Anthracenes in Soil Based on Two-Dimensional Correlation Fluorescence Spectroscopy

Polycyclic aromatic hydrocarbons (PAHs) are a kind of persistent organic pollutants in soil. Due to the low content of PAHs and the fluorescence peaks of PAHs overlapped with each other, the characteristic bands of PAHs in complex soil cannot be resolved effectively by conventional fluorescence spectrometry. In this paper, two-dimensional (2D) correlation fluorescence spectroscopy was applied to resolve the heavily overlapped fluorescence information of phenanthrenes and anthracenes in soil. According to research objectives, 9 mixed soil samples of phenanthrenes and anthracenes were prepared. And the one-dimensional (1D) fluorescence spectra of all samples were collected using LS-55 fluorescence spectrometer. Then, 2D correlation fluorescence spectra were calculated under the perturbation of the concentration of PAHs in soil. There are six auto-peaks at 367 nm, 389 nm, 409 nm, 419 nm, 434 nm, and 463 nm in synchronous 2D correlation fluorescence spectrum. The un-covered peak of 389 nm can be assigned to phenanthrene in soil. The peaks at 367 nm, 409 nm, 434 nm, and 463 nm have positive correlation with 389 nm, and thus are assigned to phenanthrene in soil. On the other hand, the peaks at 419 nm have negative correlation with 389 nm, and thus are assigned to anthracene in soil. Meanwhile, the origin of fluorescence peaks of phenanthrenes and anthracenes in soil were further verified by asynchronous 2D correlation fluorescence spectrum.