METHOD OF DETERMINING PERIOD OF MAKING REQUISITES IN DOCUMENTS FROM RELATIVE CONTENT IN VOLATILE SOLVENT MARKS THEREOF Russian patent published in 2010 - IPC G01N30/00 

FIELD: information technology.

SUBSTANCE: type of material in of a letter in marks and suitability of requisites in a document for further analysis is determined using a microscopy method. At least two analysis objects are obtained in form of an analysis sample, one of which contains document requisite marks and the other is free from marks of a piece of paper of the document. Each analysis sample undergoes thermodesorption in a continuous stream of gas for a defined period of time at given temperature to form a mixture of carrier gas and thermodesorption products. Thermodesorption products are separated from separate substances. Analysis results of samples of the mark and/or paper are obtained in form of a graph. Presence and amount of specific solvents in the mark is determined from the retention time and height of peaks on the graph. Presence of thermodesorption products of the paper in the marks with the same retention time as retention time of solvents in the analysed marks is determined from the graph. The characteristic of content of solvent in the mark is the height of the corresponding peak on the graph - chromatogram of the mark, expressed in arbitrary units (h_p) taking into account contribution of thermodesorption products from the paper (Δh) which is calculated. Further, colouring material is extracted from the marks of the samples and the obtained extracts undergo spectrophotometry in the visible region in order to determine content of dye in the sample to obtain absorption spectrum of the obtained extract on the spectrophotometre in form of a graph.

EFFECT: broader functional capabilities of the method, increased efficiency of the method, more reliable determination of the period of making document requisites, more reliable determination of their age, longer time interval for determining period of making requisites in documents.

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