Process and apparatus for measuring the concentration of a molecule of selective spectrum in a sample substance

Claim 1

A process for measuring the concentration of a molecule of selective spectrum in a sample substance, comprising subjecting the sample substance to a first monochromatic excitation light of wavelength lying within the absorption spectrum of the molecule under measurement, filtering and collecting a first light emission from the sample substance at a wavelength lying within the emission spectrum of the molecule, and determining the intensity of the monochromatic light collected, and further comprising subsequently subjecting the sample substance to a second monochromatic excitation light of a wavelength close to that of the first monochromatic light but outside the absorption and emission spectra of the molecule, filtering and collecting a corresponding second light emission from the sample substance at the same wavelength as the first, then determining the new intensity of collected light and subtracting this from the first to give a useful monochromatic light signal free from spurious signals due to diffused light or to spurious fluorescent or phosphorescent light due to traces of other molecules in the sample substance.

Claim 6

An apparatus for measuring the concentration of a molecule of selective spectrum in a sample substance, comprising an excitation monochromator arranged to subject the sample substance to a first and subsequently to a second monochromatic excitation light of wavelengths which are close together but which are within the absorption spectrum of the molecule being measured and outside the absorption and emission spectra of the same molecule respectively, a collection monochromator arranged to filter and collect corresponding light emissions from the sample substance at a wavelength within the molecule emission spectrum, and electronic processing means arranged to determine the collected light intensities corresponding to said emissions and subtract one from the other.

Claim 7

An apparatus for measuring the concentration of a molecule of selective spectrum in a sample substance, comprising an excitation monochromator arranged to subject the sample substance to a first and subsequently to a second monochromatic excitation light of wavelengths which are close together but which are within the absorption spectrum of the molecule being measured and outside the absorption and emission spectra of the same molecule respectively, a collection monochromator arranged to filter and collect corresponding light emissions from the sample substance at a wavelength within the molecule emission spectrum, and electronic processing means arranged to determine the collected light intensities corresponding to said emissions and subtract one from the other.

Claim 9

An apparatus fo measuring the concentration of a molecule of selective spectrum in a sample substance, comprising an excitation monochromator arranged to subject the sample substance to a first and subsequently to a second monochromatic excitation light at wavelengths which are close together but which are within the absorption spectrum of the molecule being measured and outside the absorption and emission spectra of the same molecule respectively, a collection monochromator arranged for filtering and collecting corresponding light emissions from the sample substance at a wavelength within the molecule emission spectrum, and electronic processing means arranged for determining collected light intensities corresponding to said emissions and subtracting one from the other, wherein said electronic processing means comprise memory means for memorizing electrical signals representing the excitation light intensities of said corresponding light emissions, signal normalising means arranged to compare said electrical signals for generating normalised signals insensitive to variations in excitation light intensity, integrator divider means arranged for taking the mean of said normalised signals produced from the first monochromatic excitation light and of the normalised signals produced subsequently by the second monochromatic excitation light, and differentiator means arranged to subtract the mean signal produced by the second monochromatic excitation light from the mean signal produced by the first monochromatic excitation light for generating a single signal constituting the useful monochromatic light signal emitted by the molecule under examination.

Claim 10

An apparatus fo measuring the concentration of a molecule of selective spectrum in a sample substance, comprising an excitation monochromator arranged to subject the sample substance to a first and subsequently to a second monochromatic excitation light at wavelengths which are close together but which are within the absorption spectrum of the molecule being measured and outside the absorption and emission spectra of the same molecule respectively, a collection monochromator arranged for filtering and collecting corresponding light emissions from the sample substance at a wavelength within the molecule emission spectrum, and electronic processing means arranged for determining collected light intensities corresponding to said emissions and subtracting one from the other, wherein said electronic processing means comprise memory means for memorizing electrical signals representing the excitation light intensities of said corresponding light emissions, signal normalising means arranged to compare said electrical signals for generating normalised signals insensitive to variations in excitation light intensity, integrator divider means arranged for taking the mean of said normalised signals produced from the first monochromatic excitation light and of the normalised signals produced subsequently by the second monochromatic excitation light, and differentiator means arranged to subtract the mean signal produced by the second monochromatic excitation light from the mean signal produced by the first monochromatic excitation light for generating a single signal constituting the useful monochromatic light signal emitted by the molecule under examination.