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Chelate titrations of Ca(2+) and Mg(2+) using microfluidic paper-based analytical devices
Shingo Karita1, Takashi Kaneta1
1Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
Analytica Chimica Acta
|May 17, 2016
Summary
We created paper-based devices for simple water testing. These microfluidic paper-based analytical devices (μPADs) allow quick, instrument-free measurement of calcium and magnesium in natural water samples.
Area of Science:
- Analytical Chemistry
- Environmental Science
- Materials Science
Background:
- Accurate determination of calcium (Ca2+) and magnesium (Mg2+) is crucial for water quality assessment.
- Traditional methods for water hardness analysis often require sophisticated instrumentation and trained personnel.
- Microfluidic paper-based analytical devices (μPADs) offer a promising platform for portable and low-cost chemical analysis.
Purpose of the Study:
- To develop and validate microfluidic paper-based analytical devices (μPADs) for the quantitative determination of Ca2+ and Mg2+ in natural water samples.
- To enable rapid, instrument-free chelate titration analysis of water hardness using μPADs.
- To assess the applicability of μPADs for analyzing diverse water matrices, including mineral, river, and seawater.
Main Methods:
- Fabrication of μPADs with integrated sample, reaction, and detection zones connected via microchannels.
- Impregnation of reaction zones with varying concentrations of ethylenediaminetetraacetic acid (EDTA) and detection zones with metal indicators (Eriochrome Black T or Calcon).
- Application of specific pH buffer solutions (pH 10 or pH 13) to differentiate between total hardness (Ca2+ + Mg2+) and Ca2+ alone.
Main Results:
- The developed μPADs successfully performed chelate titrations for determining total hardness and Ca2+ concentrations in water samples.
- Accurate measurements of Ca2+ and Mg2+ were achieved within minutes, comparable to conventional methods.
- Visual determination of metal ion concentrations was possible without the need for external instruments, demonstrating the device's simplicity.
Conclusions:
- μPADs provide a viable, cost-effective, and user-friendly alternative for on-site water hardness analysis.
- The developed method allows for the rapid and accurate quantification of Ca2+ and Mg2+ in various natural water sources.
- This technology holds potential for decentralized water quality monitoring and field applications.
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