Calcium selective test strip for water and milk

Area of Science:

• Analytical Chemistry
• Materials Science

Background:

• Accurate calcium determination is crucial for water quality and nutritional analysis.
• Existing methods for calcium measurement can be complex or lack selectivity.
• Development of rapid, selective, and field-deployable calcium sensors is needed.

Purpose of the Study:

• To develop a novel optical test strip for the selective and reversible determination of calcium.
• To characterize the performance of the test strip in terms of sensitivity, selectivity, and reproducibility.
• To validate the test strip for practical applications in analyzing calcium in diverse matrices.

Main Methods:

• Development of an ion-exchange membrane incorporating a new adamantyl-based ionophore in a plasticised PVC matrix.
• Optical detection of calcium activity via absorbance measurement at 655 nm using a standard photometer.
• Optimization of membrane composition and reaction conditions for enhanced selectivity and performance.
• Application and validation against a reference method for calcium determination in water and milk samples.

Main Results:

• The developed test strip demonstrated selective and reversible calcium detection based on an ion-exchange mechanism.
• Linear response to calcium activities was observed in the range of 0.050 to 135 mM.
• Good reproducibility was achieved, with intermembrane and intramembrane relative standard deviations (RSD) of 6.2% and 3.4%, respectively.
• Successful application and validation in determining calcium ion concentrations in various water and milk samples.

Conclusions:

• The novel optical test strip provides a reliable and selective method for calcium determination.
• The test strip's performance characteristics make it suitable for practical analysis of calcium in environmental and food samples.
• This method offers a valuable alternative to existing calcium determination techniques, particularly for field applications.