Correction method of effect of soil moisture on the fluorescence intensity of polycyclic aromatic hydrocarbons based on near-infrared diffuse reflection spectroscopy

• Published in: Environmental pollution (1987) Vol. 269; p. 116150
• Main Authors: Dong, Guimei, Li, Xiaotong, Yang, Renjie, Yang, Yanrong, Liu, Haixue, Wu, Nan
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15-01-2021
• Subjects: Correction; Fluorescence spectra; Near infrared diffuse reflectance spectrum; Polycyclic aromatic hydrocarbons; Polycyclic Aromatic Hydrocarbons - analysis; Soil; Soil moisture; Soil Pollutants - analysis; Spectroscopy, Near-Infrared; Near infrared diffuse reflectance spectrum; Polycyclic aromatic hydrocarbons; Soil moisture; Correction; Fluorescence spectra
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2020.116150

Soil moisture has a strong impact on the fluorescence intensity of PAHs, which is undoubtedly posing a challenge for the development of rapid real-time fluorescence detection technology of PAHs in soil. In this work, NIR diffuse reflectance spectroscopy was used to correct the fluorescence spectra of PAHs in order to reduce the effect of the soil moisture. To establish the correction method, eight soil samples with different moisture contents and a given phenanthrene concentration (8 mg/g) were prepared. The fluorescence and NIR diffuse reflectance spectra were collected for of all samples. It was found that the fluorescence spectra of the soil samples that vary with the moisture content together with the NIR diffuse reflectance spectra were considered for the correction of the fluorescence intensity of phenanthrene related to the moisture content. The results showed that the ratio of the fluorescence intensity at 384 nm to the NIR diffuse reflectance spectrum absorbance at 5184 cm−1 can be used as a correction factor to reduce the effect of the soil moisture on the fluorescence intensity of phenanthrene in the soil. The validity of the correction method was verified by the quantitative analysis of PAHs with different concentrations and soil moisture contents. The results showed better linearity between the fluorescence intensity and the concentration of PAHs after the correction (with a correlation coefficient R of 0.99) than before the correction (with R of 0.86). The relative prediction errors for three unknown samples decreased from 19%, 51% and 40% before the correction to 5%, 13% and 0.44% after the correction, respectively, indicating the feasibility of the detection of PAHs in the soil by the combination of fluorescence and NIR diffuse reflectance spectroscopy.
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•A correction method to reduce the effect of soil moisture on fluorescence intensity of polycyclic aromatic hydrocarbons.•NIR diffuse reflectance spectroscopy was used to correct the fluorescence spectroscopy of polycyclic aromatic hydrocarbons.•It is feasible to detect polycyclic aromatic hydrocarbons in soil by fluorescence and NIR diffuse reflectance spectroscopy.•After correction fluorescence spectra showed better performance than before correction.
A correction method based on NIR diffuse reflectance spectra was proposed to reduce the effect of soil moisture on the fluorescence intensity of PAHs.