OFFICE SCANNER USE FOR OBTAINING ANALYSIS OBJECTS DIGITAL IMAGES AND THEIR COLOR CHARACTERISTICS COMPUTER DETERMINATION

Abstract

Recently, the practice of analytical chemistry has included the method of chemical chromaticity, based on the measurement of the integral characteristics of the color reflected from the surface of the analyte and which makes it possible to distinguish between spectrally close substances. With the spread scanners and computer programs for color image processing, a fast and objective method for assessing the color characteristics of colored samples has appeared, opening up the prospect of using chemical chromaticity in the chemical analysis of various objects in the absence of special spectrophotometric equipment or with minimal use of it. Thus, the process of chemical chromaticity analysis is divided into two parts: obtaining a high-quality digital image of the analyzed object and processing the resulting file in a graphics editor. The article describes in detail the methodological issues of scanning solutions, powders, surfaces of dosage forms using an office scanner and processing the resulting digital images in a graphics editor. On the example of model samples, standard solutions of salts FeCl3⋅6H2O, CoCl2⋅6H2O, CuSO4⋅5H2O, it is shown that in the range of 6–60 g/l their concentrations can be determined with sufficient accuracy as with using its absorption spectra (registered on a Lambda 9 PerkinElmer spectrophotometer) or spectra of diffuse reflection (on the same instrument using a scanning sphere B013–9941), and when using an desktop scanner HP scanjet 2200c with HP PrecisionScan LTX 1.2 software, followed by digital processing of  the scan in Photoshop CS3. Acquisition and analysis of digital images of analytes can be considered as an inexpensive replacement for spectrophotometry in a certain interval of concentrations, comparable with it in terms of accuracy and reliability of determinations. The introduction of this technique into the educational process makes it possible to increase the efficiency of teaching students when mastering the skills of converting color characteristics into optical density values and to better understand the principles of the science of color and light absorption. The method can be made mobile for analysis of results in remote areas using a portable scanner powered by battery.