Patent ID: 7846390

Claim:
An apparatus for measuring concentrations of fuel mixtures based on inducing deep-layer fluorescence and using 90° excitation-emission geometry, comprising: a source of ultraviolet light for generating an excitation light beam; a sample holder, an elongated sample container supported by the sample holder and configured to contain the fuel mixtures in the path of the excitation light beam, the sample container having a vertical longitudinal axis, the sample container being formed from an optically transparent material such that the excitation light beam is directed within the sample container along a first direction parallel to the excitation light beam and onto the fuel mixtures; a screen fixedly disposed adjacent the sample holder and sample container, the screen having a vertical slit defined therein, the vertical slit extending in the same orientation as the vertical axis of the sample container and adapted for diffracting fluorescent light emitted from the sample container along a second direction orthogonal to the first direction of the excitation light beam; a monochromator disposed in the path of light diffracted through the slit in the screen for filtering the diffracted light to an emission wavelength, the monochromator being successively scannable over a spectrum of emission wavelengths; at least one lens disposed between the slit defined in said screen and said monochromator, the at least one lens being optically suited for focusing the light diffracted through the slit onto the monochromator; a photomultiplier, the monochromator being disposed between the slit and the photomultiplier, the photomultiplier generating a test signal proportional to the intensity of the diffracted light; means for generating a trigger signal proportional to the intensity of the excitation light beam; a signal analyzer receiving the reference signal and the test signal and thereafter generating an output signal corresponding to the intensity of the fluorescent light emitted from the sample container; and means for moving the sample holder in the path of the excitation light beam so that the light diffracted through the vertical slit in the screen corresponds to fluorescent light emitted from successively deeper portions of the fuel mixtures contained within the sample container resulting from deeper penetration of the excitation light beam into the sample container.