Correction for the effect of soil types on the fluorescence intensity of polycyclic aromatic hydrocarbons

A correction method was proposed and established to reduce the effect of soil types on the PAHs fluorescence intensity based on near-infrared (NIR) diffuse reflectance spectroscopy. The benzo [ghi] pyrene in soil was as the research object. Five types of soil samples with concentration of 1 mg/g benzo [ghi] pyrene were prepared respectively. The fluorescence spectra and NIR diffuse reflectance spectra of all samples were collected. The effects of soil types on the fluorescence spectra and NIR diffuse reflectance spectra were studied. It was found that the effect of soil types on PAHs fluorescence intensities was reduced by dividing the fluorescence intensity by the transformed diffuse reflectance at 4688 cm^-1. In order to verify its effectiveness, the established correction method was used to quantitatively analyze the benzo [ghi] pyrene concentration in soil. The correlation coefficients R² of linear fitting between the fluorescence intensities and concentrations of benzo [ghi] perylene are 0.90 and 0.95 before and after correction, respectively. The average relative prediction error decreased from 35.7% before the correction to 8.71% after the correction. The results show that the established correction method can effectively reduce the effect of soil type on PAHs fluorescence intensity based on NIR diffuse reflectance spectrum. The research can provide theoretical basis and technical support for the accurate and rapid detection of PAHs in soil by fluorescence spectroscopy.