Patent ID: 8455845

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