Determination of Chromium and Manganese in Steel
Using Digital Photometry of Solutions

 Jason DR Vedad1, Josefina L. Solivas1, Jose H. Santos2 and
Ernesto J. del Rosario1*

1Institute of Chemistry, College of Arts and Sciences
University of the Philippines Los Baños, Laguna, Philippines
2Chemical Sciences Programme, Faculty of Science
Universiti Brunei Darussalam, Bandar Seri Begawan, Brunei Darussalam
corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.



The chromium and manganese contents of a steel sample were determined using digital photometric analysis. Digital still photographs of dichromate and permanganate solutions were taken using 10-megapixel (MP) and 12-MP digital cameras. RGB values were determined using the RGB Analysis of Image Colors and SI ColorPicker which are free-access software. G-B and a*-b* plots were constructed in order to calculate the analyte concentrations, which were then compared with those obtained by conventional spectrophotometric analysis. The concentrations obtained with the two digital cameras showed no significant differences at 95% confidence level from those calculated based on RGB values using the two software. Use of G-B plots resulted in greater accuracy than a*-b* plots for calculating chromium and manganese concentrations. Digital photometry (color image processing) was found to be reproducible and accurate and is a cheaper alternative to conventional spectrophotometry for determining the chromium and manganese contents of steel.


Steel consists mainly of iron and small amounts of carbon plus alloying metals like manganese, chromium, vanadium. These added metals make the steel harder and stronger but reduce ductility. It contains 100 ppm - 10% chromium and 0.1% - 1% manganese (Ashby and Jones 1992). Colorimetric analysis of chromium and manganese is used in some standard methods although spectroscopic methods such as atomic absorption and inductively-coupled plasma emission spectroscopy, as well as neutron activation analysis and X-ray fluorometry are more . . . . . read more



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