Simple colorimetric assay using pectin hydrogel reagent coupled with camera-based photometry for trace arsenic...

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Arsenic contamination in drinking water poses significant health risks.
• The World Health Organization (WHO) recommends a maximum arsenic limit of 0.01 mg/L in drinking water.
• Accurate and accessible methods for arsenic detection are crucial for public health protection.

Purpose of the Study:

• To develop a novel pectin-based hydrogel reagent for selective arsenic detection.
• To establish a colorimetric assay for quantifying arsenic in water samples.
• To validate the developed method against conventional analytical techniques.

Main Methods:

• Preparation of a leucomalachite green (LMG) entrapped pectin hydrogel reagent.
• Colorimetric reaction of arsenic with potassium iodate and LMG in a buffer solution.
• Quantification of color intensity using camera-based photometry and ImageJ software (RGB analysis).

Main Results:

• The assay demonstrated selective reaction with arsenic, outperforming other tested metals.
• A dynamic detection range of 0.003-1 mg/L was achieved, encompassing the WHO guideline value.
• High recovery rates (97-109%) and good precision (4-9%) were observed.
• Results from real water samples correlated well with inductively coupled plasma optical emission spectrometry.

Conclusions:

• The developed pectin-based hydrogel assay provides a promising tool for on-site, quantitative arsenic analysis in water.
• The method is sensitive, selective, and utilizes readily available technology, making it suitable for routine monitoring.
• This approach contributes to ensuring the safety of drinking water supplies by enabling efficient arsenic detection.