Microanalysis based on paper device functionalized with cuprizone to determine Cu²⁺ in sugar cane spirits using a...

Area of Science:

• Analytical Chemistry
• Food Science
• Materials Science

Background:

• Copper (Cu²⁺) analysis is crucial for quality control in sugarcane spirits.
• Existing methods for Cu²⁺ detection can be complex and time-consuming for in-situ applications.

Purpose of the Study:

• To develop and validate a novel paper-based test strip for the qualitative and quantitative analysis of Cu²⁺ in sugarcane spirits.
• To enable rapid, portable, and cost-effective in-situ monitoring by producers.

Main Methods:

• Functionalization of paper test strips with cuprizone.
• Optimization of reaction conditions using a Box-Behnken experimental design.
• Qualitative analysis by untrained volunteers and quantitative analysis using a smartphone-based digital image method.

Main Results:

• The qualitative method achieved 93% accuracy.
• Quantitative analysis showed statistical agreement with reference methods, with a dynamic linear range of 2–13 mg L^-1.
• Detection and quantification limits were 0.034 and 0.103 mg L^-1, respectively, with good precision (RSD 4.3%) and recovery (80–103.8%).

Conclusions:

• The developed paper-based test strip is a viable tool for rapid in-situ Cu²⁺ analysis in sugarcane spirits.
• The method offers simplicity, portability, and speed, making it suitable for producers.
• The combination of a test strip and smartphone imaging provides a reliable analytical solution.