Separation of the overlapped humic acid and BGP characteristic peaks using two-dimensional correlation fluorescence-UV-vis spectroscopy

Fluorescence spectroscopy has been widely used to detect polycyclic aromatic hydrocarbons (PAHs) in the environment. However, the interference of coexisting humic acids (HA) in the environment poses a great challenge to the qualitative and quantitative detection of PAHs using fluorescence spectroscopy. In this study, the spectral properties of benzo [ghi] perylene (BGP) and HA were investigated based on fluorescence and UV-vis spectroscopy combined with two-dimensional (2D) correlation analysis. Under the external disturbance of HA concentration, the homo-2D (fluorescence, UV-visible) correlation and hetero-2D fluorescence-UV-visible correlation spectral characteristics of the mixed samples of HA and BGP were studied, and the effect of HA on the fluorescence of BGP was investigated. It can be inferred that the fluorescence peak at 478 nm come from BGP, and the fluorescence peaks at 442 nm and 533 nm, UV absorption peak at 233 nm come from HA. Meanwhile, asynchronous two-trace two-dimensional (2T2D) fluorescence correlation slice spectra at 533 nm were obtained. The slice spectral intensity at 478 nm was extracted to quantify the BGP concentration in mixture. The results showed that the slice spectral intensity and BGP concentration had a good linear relationship with the coefficient of determination R2 = 0.96. This research provides a way to further study the separation method of HA and PAHs or explore the correction method of the effect of HA on PAHs.