A strategy to reduce the effect of organic matter on fluorescence intensity for improving the detection accuracy of polycyclic aromatic hydrocarbons in soil

Han Zhang; Tao Lei; Xiaotong Li; Renjie Yang; Guimei Dong; Yanrong Yang

doi:10.1016/j.saa.2023.122446

A strategy to reduce the effect of organic matter on fluorescence intensity for improving the detection accuracy of polycyclic aromatic hydrocarbons in soil

Spectrochim Acta A Mol Biomol Spectrosc. 2023 May 15:293:122446. doi: 10.1016/j.saa.2023.122446. Epub 2023 Feb 4.

Authors

Han Zhang¹, Tao Lei¹, Xiaotong Li¹, Renjie Yang², Guimei Dong³, Yanrong Yang¹

Affiliations

¹ College of Engineering and Technology, Tianjin Agricultural University, 22 Jinjing Road, Tianjin 300384, China.
² College of Engineering and Technology, Tianjin Agricultural University, 22 Jinjing Road, Tianjin 300384, China. Electronic address: rjyang1978@163.com.
³ College of Engineering and Technology, Tianjin Agricultural University, 22 Jinjing Road, Tianjin 300384, China. Electronic address: guimeidong@gmail.com.

PMID: 36764166
DOI: 10.1016/j.saa.2023.122446

Abstract

Fluorescence spectroscopy has been used for rapid detection of PAHs in soil, but soil organic matter (SOM) produces strong interference to the fluorescence intensity of PAHs, which restricts the application of fluorescence spectroscopy for rapid detection of PAHs in soil. A correction method of reducing the interference of SOM on PAHs fluorescence intensity was proposed combining fluorescence and near-infrared (NIR) spectroscopy. Six soil samples with different concentrations of humic acid (HA) at a given phenanthrene concentration (5 mg/g) were prepared and scanned for obtaining the fluorescence and NIR diffuse reflectance spectra. The spectral data showed that the fluorescence intensity and NIR diffuse reflectance had an approximate trend with the change of HA concentration. It was found that the NIR diffuse reflection at 4672 cm^-1 as a calibration factor could effectively reduce the interference of HA on the fluorescence intensity of phenanthrene. Subsequently, a standard curve for the quantitative analysis of phenanthrene in soil was established based on the fluorescence intensity before and after calibration. For the unknown samples, the predicted average relative errors of the standard curves before and after calibration were 27.46 % and 9.00 %, respectively. The results showed that the proposed correction method could reduce the interference of HA on the quantitative analysis of PAHs, and provide a reference for eliminating the interference constraint of fluorescence spectroscopy technique for rapid real-time detection of PAHs in soil.

Keywords: Correction method; Fluorescence spectroscopy; Humic acid; Near-infrared spectroscopy; Polycyclic aromatic hydrocarbons (PAHs); Soil.