Simple method for colorimetric spot-test quantitative analysis of Fe(III) using a computer controlled hand-scanner

This paper describes a very simple and rapid method for colorimetric spot-test determination of Fe(III) utilizing a hand-scanner. Artificial neural networks with back propagation algorithm coupled with an orthogonal array design were applied to the modeling and optimization of scanner parameters. Orthogonal design was utilized to design the experimental protocol, in which scanner parameters including dot per inch (dpi), brightness (btn), contrast (ent), and mixed gamma (mgm) were varied simultaneously. Then, using ANNs, optimum experimental conditions in terms of sensitivity were generated. Calibration curves were obtained by plotting first principal component obtained from color intensities (red, green, and blue) against the concentration of Fe(III) from 6 to 45 mmol l(-1) Fe(III). Error less than 4% was obtained for all of the experiments. The method was successfully applied for analysis of Fe(III) in a synthetic iron steel. Totally, the obtained results showed that the method is applicable for accurate, precise, rapid, and low cost colorimetric analysis including spot-test procedures. (C) 2002 Elsevier Science B.V. All rights reserved.