Uso de imagem digital obtida por processo fotográfico para a quantificação de fósforo existente em amostras de solo e/ou fertilizantes

Abstract

The present work aims to use digital imaging for the quantification of existing phosphorus in soil and/or fertilizer samples as an alternative to the use of UV-VIS (ultra violet-visible) spectrophotometer. An equipment was built that enables the This equipment was designed to facilitate the obtention of the intensities of light obtaining the intensities of light passing through the samples. The light power was evaluated in order to that the same photographic process would guarantee good quality photos, photos that make possible to read the light intensity. First the calibration lines were obtained on the blue stamp ink base avoiding reagent costs; In the second phase the calibration In the second phase the calibration lines were obtained on the basis of reagents suitable for the determination of phosphorus Then water soluble phosphorus was determined in the fertilizers Urea, Double superphosphate and 12- 24-12. Images were taken of the colored solutions previously placed in collection tubes adapted to function as a cuvette in the created equipment, where the light source is a 5 W fluorescent lamp. 5 W fluorescent lamp. The photos were transferred to an image editing program, where they were editing program, where the sides were cut out and the central part of each photo in an area of 15 mm x 15 mm, then the intensities of light passing through each sample were read. sample. The values were exported to Microsoft Excel, the absorbances were calculated and correlated with their concentrations, thus obtaining calibration curves that facilitated the interpolation of phosphorus concentrations in fertilizer samples. For the feasibility analysis of the method, the results obtained were compared with the results of the spectrophotometric spectrophotometric method. With the results of the comparison, it was possible to conclude that the digital imaging method is a reliable and promising alternative for the determination of phosphorus in soils and/or fertilizers, and that with the application of this method the impact of the problem raised in this research. (TRADUÇÃO NOSSA)