Patent ID: 7427508
Filing Date: 2008-09-23
Classification: G01N

Abstract:
1. A method for authenticating the composition of multicomponent mixtures and/or detecting the presence of impurities in multicomponent mixtures comprising: a. dividing the light of a broadband source of optical radiation into spectral components, and/or selecting the assigned narrow band spectral sections of the probing beam with a spectral width of Δ b. focusing the selected narrowband light onto a sample under analysis; c. irradiating a sample of a known mixture K and a sample of an unknown mixture U by turns with the focused probing beam at the selected wavelengths λ d. collecting the probing light falling on the sample, passed through the sample or reflected by the sample to a photodetector and collecting spectral sections of the luminescent light to another photodetector; e. measuring the intensity values of the probing light and the luminescent light collected onto the photodetectors for each of the selected wavelengths λ f. determining the relative intensity of the collected light passed through the sample, or reflected by a the sample, at each of selected wavelengths λ where T K (λ m ),T U (λ m )—intensity values of passed or reflected light for samples of a known K mixture and unknown U mixture, normalized for the intensity of incident radiation falling on a sample at the corresponding wavelength; L K (λ m ,λ n ),L U (λ m ,λ n )—intensity values of the luminescent light irradiated by a sample of a known K mixture and unknown U mixture within the specified sections λ 1 , λ 2 , . . . λ n of the predetermined range of wavelengths λ j with light excitation within the specified sections λ 1 , λ 2 , . . . λ m of the predetermined range of wavelengths λ i , normalized for intensity of incident radiation falling on a sample at the corresponding wavelength; I T K (λ m ),I T U (λ m )—intensities of passed or reflected light for samples of a known K mixture and an unknown U mixture measured at the specified sections λ 1 , λ 2 , . . . λ m of the selected range of the incident light from the predetermined range λ i ; I L K (λ m ,λ n ),I L U (λ m ,λ n )—intensities of the luminescence radiated by a sample of a known K mixture and a sample of an unknown U mixture measured at the selected wavelength λ 1 , λ 2 , . . . λ n of the selected range of wavelengths λ j with light excitation within the specified sections λ 1 , λ 2 , . . . λ m of the predetermined range of wavelengths λ i ; I 0 K (λ m ),I 0 U (λ m )—intensity of incident probing radiation falling on an appropriate samples at the time of performing measurements; g. comparing the corresponding relative intensity values of the light passed through the sample, or reflected by the sample, at each of the selected wavelengths λ where m, n—the number of selected wavelengths from the predetermined spectral ranges λ δ—a value of allowable deflections of the compared values for the unknown mixture under analysis from the corresponding values for the similar values of a standard sample of a known mixture; h. determining the presence or absence of foreign impurities in the mixture by the following expressions: whereas, if C T (λ i )=C L (λ i , λ j )=0±δ, there are no foreign impurities in the sample under analysis, while if there are ranges with C T (λ i )>0±δ, and/or C L (λ i , λ j )≠0±δ, undesirable impurities are present in the sample.