Preliminary Research on the Analysis of Chromium(III) Based on Digital Image Processing Method Utilizing Gold Nanoparticles as Colorimetric Sensor

Gold nanoparticles (AuNPs) have been successfully synthesized using L-Ascorbic Acid as a reducing agent and p-Aminobenzoic Acid as a capping agent. These AuNPs were used to detect and quantify Chromium(III) as a pollutant utilizing its unique characteristic called surface plasmon resonance (SPR). The change of SPR and color of AuNPs then was employed to determine the concentration of Cr(III) by using colorimetric and Digital Image Colorimetric methods. Digital Image Colorimetry allowed to development of an easier and cheaper way to detect and quantify Cr(III). AuNPs capped p-aminobenzoic acid (AuNPs-PABA) were synthesized at room temperature without using any heating method. Then synthesized AuNPs-PABA were characterized using UV-Visible spectrometer and Transmission Electron Microscope. This AuNPs-PABA then got contacted to Cr(III) and color-changing happened in AuNPs-PABA was analyzed using UV-Vis Spectrometer and captured for Digital Image Colorimetric. The result showed that Digital Image Colorimetric method has a very big potential to be developed for AuNPs-based detection and quantification of Cr(III) as confirmed by good linearity of AuNPs-PABA-Cr(III) respect with Difference Intensity of Red Color Component, wider dynamic range, and Lower Limit of Detection (LoD).