Ultraviolet Fluorescence-Based Quantitative Detection of Polycyclic Aromatic Hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs), mainly produced by incomplete combustion of organic materials in ship engines as well as in industry, has been considered one of the major hazardous substances in water-based ecotoxicology. Its real-time quantitative monitoring has thus been becoming increasingly important, particularly that with ultrahigh sensitivity. In this work, we demonstrated an ultraviolet (UV) fluorescence with an optical feedback for the highly sensitive quantitative detection of polycyclic aromatic hydrocarbons (PAHs). A fluorescence sensor is presented owing to its intrinsic fluorescence properties in the UV spectral range. This sensor, where an optical feedback is introduced with an aluminum film coated on a sensor chip, enhances fluorescence via increasing efficiency of both dye excitation and emission collection. The experimental results include the linear response of the UV fluorescent signal-to-concentration over a broad concentration range, with the signal-to-concentration slope representing a threefold enhancement over conventional fluorescence devices. The sensor device features such characteristics as the limit of detection (LOD) of 0.49 part per billion (ppb), signal accuracy > 92.5%, coefficient of variation < 5% (for signal reproducibility), the detection time of 3 s, and temperature error < 5%. Upon miniaturization of the format, the device presented may find an use for ultrasensitive in situ detection of PAHs in water.

Automated summary

This study demonstrated a UV fluorescence sensor with optical feedback for highly sensitive quantitative detection of PAHs. The sensor showed good linear response and low detection limit, suitable for in situ detection of PAHs in water.