Fabrication, Validation Methods and Interference Test of Beads for Detection Colorimetic of Fe(II)

Colorimetry is an analytical method based on the visualization of color changes. This method is simple, inexpensive, and efficient so that it can be applied to detect dissolved ferrous metal ions in the form of Fe (II). Fe (II) ions can form complex compounds with 1,10-phenanthroline ligands in carrageenan matrices of iota and kappa types made in the form of beads. In this study, interference testing and method validation have been conducted to optimize and evaluate beads in the colorimetric detection of Fe (II). The results exhibited that Ni (II) and Cu (II) ions as interferents lowered the color intensity of the complex compound of Fe (II) with 1,10-phenanthroline at concentrations starting from 10 mg/L. Besides, Fe (III) improved the colorimetric detection color intensity from the lowest concentration of 3 mg/L, while Mg (II), at 25 mg/L, decreased the color intensity. Furthermore, the standard curve exposed good linearity. Based on the standard deviation and the standard curve slope, the beads limit in the colorimetric detection of Fe was 0.17 mg/L. The quantification limit obtained through calculations was 0.57 mg/L. The precision could be considered good. The beads interference test for colorimetric detection of Fe (II) had good accuracy with a recovery value of 93-102%. Keywords: Bead, Colorimetric Detection, Validation, Interference Test