Development of an Ultrasound-Assisted Slurry Sampling-Based Method for Determination of Metals in Rice Samples Using...

Area of Science:

• Analytical Chemistry
• Environmental Science
• Food Science

Background:

• Accurate determination of essential minerals like calcium (Ca), iron (Fe), and zinc (Zn) in rice is crucial for human nutrition and health.
• Traditional methods for elemental analysis in food matrices often involve complex sample preparation, generating significant waste.
• Development of green and efficient analytical techniques is essential to minimize environmental impact and improve analytical workflow.

Purpose of the Study:

• To develop and optimize a green analytical method for determining Ca, Fe, and Zn in rice samples.
• To utilize slurry sampling combined with multivariate optimization for enhanced method performance.
• To validate the developed method for its suitability in routine rice sample analysis.

Main Methods:

• Slurry sampling technique utilizing 0.25 g of rice sample in 0.7 mol L^-1 HNO₃ and 0.31% Triton X-100.
• Ultrasound bath treatment for 7.5 minutes for efficient sample homogenization.
• Multivariate optimization using two-level fractional factorial design and Doehlert design to determine optimal experimental conditions.

Main Results:

• Achieved low limits of quantification (LOQ) for Ca (4.9 mg kg^-1), Fe (1.6 mg kg^-1), and Zn (0.22 mg kg^-1).
• Demonstrated high precision with repeatability values of 4.4% (Ca), 3.6% (Fe), and 2.2% (Zn) (n=7).
• Accuracy confirmed through spike tests (90-108% recovery) and statistically insignificant differences compared to standard acid decomposition methods (paired t-test, 95% confidence level).

Conclusions:

• The developed green slurry sampling method is accurate, precise, and efficient for determining Ca, Fe, and Zn in rice.
• This method offers a sustainable alternative to conventional techniques, reducing sample preparation time and waste generation.
• The validated method is suitable for routine analysis of essential minerals in rice, contributing to food quality and safety assessments.