U.S. Patent No. 7,919,325, issued on April 5, 2011 to Authentix, Inc. of Addison, TX, discloses a method of using an anti-Stokes marker for authentication of liquid products.
According to the ’325 patent, covert markers are useful for detecting product counterfeiting, product adulteration, and unauthorized distribution and sales. Fluorophores (e.g., aromatic organic molecules) have previously been used as markers which can be added to a material for later detection of the characteristic fluoroescence upon irradiation by an excitation source to confirm authenticity. However, the fluorescent signal of interest can be difficult to resolve from background signals, due to various factors such as broad absorption and emission bands in the UV/visible portion of the spectrum, photobleaching, and quenching of the signal due to absorption by the sample. The ’325 patent discloses a system and method for using markers that exhibit anti-Stokes luminescence, in which the wavelength of the emitted light is shorter than the wavelength of the excitation light. By adding particular anti-Stokes markers to a liquid (e.g., perfumes, beverages, petroleum products) and later detecting and quantifying the detected light having the characteristic wavelength of the marker, the ’325 patent discloses identifying and authenticating the liquid while avoiding some of the problems previously encountered when using fluorescence.
According to its website, Authentix is “the global leader in authentication and provides brand protection solutions for the oil and gas, pharmaceutical, consumer, tobacco, spirits, and agrochemical industries.” Among its patented technologies is “regulatory approved forensic markers for ingestible products such as pharmaceuticals, foods and beverages.” According to the USPTO database, Authentix owns 34 U.S. patents.
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