A method for detecting polymer-based drag reducer additives in gasoline includes placing a sample in a high UV-transmittance receptacle having at least two transparent adjacent sides and irradiating the same with a pulsed laser beam; detecting laser-induced fluorescence wavelength resolved spectrum at a 90° angle relative to the laser beam through the adjacent side of the receptacle and a slit in a diffraction screen adjusting the position of the receptacle and de-focusing the collimating lenses so that the low resolution fluorescence wavelength-resolved spectrum appears with a first peak at about 380 nm and a second peak at about 430 nm; recording the laser-induced fluorescence wavelength-resolved spectra within a defined time-gate starting at the end of the temporal span of the laser pulse; and comparing the percentage intensity of the first peak relative to the second peak to that of a gasoline sample free of any polymer-based drag reducer additives.