Fig. 1. Experimental detection device for methanol fluorescence spectrum

Fig. 2. Physical drawing of experimental testing platform for two-dimensional fluorescence spectrum

Fig. 3. Fluorescence measurement of solution

Fig. 4. Schematic diagram of molecular energy level transition

Fig. 5. Two-dimensional fluorescence spectra. (a) Pure water; (b) pure methanol

Fig. 6. Fluorescence spectra of benzene under different A and influence of B on fluorescence intensity of benzene. (a)(c)(e) Fluorescence spectra of benzene under different A; (b)(d)(f) influence of B on fluorescence intensity of benzene

Fig. 7. Fluorescence spectra of toluene under different C and influence of B on fluorescence intensity of toluene. (a)(c)(e) Fluorescence spectra of toluene under different C; (b)(d)(f) influence of B on fluorescence intensity of toluene

Fig. 8. Comparison of fluorescence spectra. (a) Pure benzene solution with mass concentration of 200 mg/L; (b) benzene methanol-water solution with mass concentration of 200 mg/L when B is 15%‒90%; (c) pure toluene solution with mass concentration of 20 mg/L; (d) toluene methanol-water solution with mass concentration of 20 mg/L when B is 5%‒90%

Fig. 9. Spectral repeatability plots of benzene under different mass concentrations

Fig. 10. Spectral repeatability plots of toluene under different mass concentrations

Fig. 11. Schematic diagrams of benzene molecule surrounded by methanol. (a) Three-dimensional; (b) two-dimensional

Fig. 12. Influence of methanol volume fraction on the fluorescence quenching effect. (a) Benzene solution with mass concentration of 200 mg/L; (b) toluene solution with mass concentration of 40 mg/L