Detection of Gasoline Adulteration by a High-Sensitivity Optical Fiber Sensor Based on Matrix Demodulation Technology
摘要
The illegal adulteration of gasoline with kerosene seriously compromises vehicle performance, environmental safety, and public health. However, prevailing detection techniques are often hindered by ambient temperature fluctuations, making on-site rapid and accurate measurement challenging. This work presents a dual-parameter photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR), which enables simultaneous detection of gasoline adulteration (kerosene concentration in gasoline) and ambient temperature. By coating a polydimethylsiloxane (PDMS) layer atop the gold film within a microchannel, the sensor achieves simultaneous detection of gasoline adulteration and ambient temperature. The high performance of the sensor results from the systematic optimization of six structural parameters, such as the polishing distance. For kerosene concentration detection in the range of 0–20%, it achieves a maximum wavelength sensitivity of 52 nm/%, a limit of detection (LOD) as low as 0.0043%, and a maximum figure of merit (FOM) of 0.7177%−1. For temperature sensing within 0–50 ℃, a high sensitivity of -5 nm/℃ is attained. To address the critical challenge of cross-sensitivity in single-parameter sensing caused by temperature variations, this study innovatively utilizes the distinct responses of dual resonance peaks to establish a sensitivity matrix. This methodology facilitates the simultaneous measurement and effective decoupling of kerosene concentration and ambient temperature. Thus, the presented strategy provides a viable solution for fuel adulteration detection in complex thermal environments, effectively resolving the issue of multi-parameter cross-sensitivity.