Analytical Sciences

Difluoroboron-Curcumin Doped Starch Film and Digital Image Colorimetry for Semi-Quantitative Analysis of Arsenic

Aree CHOODUM,* Vanida JIRAPATTANASOPHON,* Chanita BOONKANON,* Tarawee TAWEEKARN,* and Worawit WONGNIRAMAIKUL*,**

*Integrated Science and Technology Research Center, Faculty of Technology and Environment, Prince of Songkla University, Phuket Campus, Kathu, Phuket 83120, Thailand
**Research Program: The Development of Management System for Reduction and Control of Water Contamination and Distribution in Songkhla Lake Basin and the Western Coastline of the South of Thailand, Center of Excellence on Hazardous Substance Management (HSM), Bangkok 10330, Thailand

This work presents a novel, simple, rapid, and cost effective method for semi-quantitative analysis of arsenic(III) in water sample. The method was based on the digital image colorimetry (DIC) of difluoroboron-curcumin doped starch film (BF₂-cur-film) and arsenic ion in water. A red BF₂-cur-film (9.4 μm) was fabricated by entrapped difluoroboron-curcumin (BF₂-curcumin, particle size of 60 – 113 nm) in tapioca starch film. When the standard solution of arsenic (1 mL) was added into small plastic tube containing BF₂-cur-film on its inner lid, blue solution (λ_max at 610 nm) was observed instead of orange color in blank solution (λ_max at 495 nm). When BF₂-cur-film was used in conjunction with DIC, a wide linear range of 0 – 10 mg L⁻¹ with good linearity (R² > 0.99) was obtained from green channel with low detection limit of 0.04 mg L⁻¹. Moreover, good precision (0.9 – 1.2%RSD, n = 4 days) and accuracy (0.03% relative error) were also achieved.

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