Naked eye detection of inorganic arsenic in aqueous solution using difluoroboron-curcumin

Abstract

This research presented a new naked eye detection method for the determination of arsenic (As) in water samples. The method is based on changes in the color and visible absorbance of difluoroboron-curcumin (BF₂-curcumin), which yielded an orange solution with the maximum absorbance at 509 nm. In the presence of arsenic, the color of BF₂-curcumin solution changed from orange to blue and the absorbance was measured by UV-visible spectrophotometry at 632 nm. This method was applicable in both BF₂-curcumin solution and BF₂-curcumin coated resin. Under the optimal conditions, the detection limits of As(III) achieved by means of UV-visible spectrometry, naked-eye detection with BF₂-curcumin solution and naked-eye detection with BF₂-curcumin-coated resin were found to be 0.26, 25 and 30 µM, respectively. In addition, this method can be applied to determine total As in water samples and waste water samples. The limit of detection of total As were 0.26 µM and 0.1 mM for UV-visible spectrophotometry and naked eye detection with BF₂-curcumin-coated resin, respectively. The advantages of this new colorimetric method are simple. Rapid, low cost and applicable for naked-eye determination of As in water samples.