Highly Precise Laser-Induced Breakdown Spectroscopy Analysis of Major Mineral Nutrients in Edible Salts Using...

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Laser-induced breakdown spectroscopy (LIBS) is a powerful technique for elemental analysis.
• Improving the precision of LIBS measurements, especially for inhomogeneous samples like salts, remains a challenge.
• Current methods often struggle with sample preparation and achieving reproducible results.

Purpose of the Study:

• To enhance the measurement precision of LIBS for analyzing essential minerals in edible salts.
• To develop and validate a novel approach combining a hydrophilicity-enhanced substrate with an alternating laser-ablation data sampling (ALADS) scheme.
• To assess the performance of this integrated method for quantifying potassium (K), magnesium (Mg), calcium (Ca), and sulfur (S) in various commercial salt products.

Main Methods:

• Utilized a hydrophilicity-enhanced solid substrate designed as a miniaturized salt pond for sample preparation.
• Applied an alternating laser-ablation data sampling (ALADS) scheme to extract multiple precise measurements from LIBS spectra.
• Analyzed five commercially available edible salt samples from different geographical origins (Australia, Bolivia, France, South Korea).

Main Results:

• The combined substrate and ALADS approach significantly improved sample homogeneity compared to traditional drop-and-dry methods.
• ALADS provided highly consistent measurements despite the inherent inhomogeneity of dried salt crystals.
• Achieved remarkable measurement precision for K, Mg, Ca, and S, with low limits of detection (e.g., 0.64 mg/kg for K).

Conclusions:

• The developed LIBS methodology, integrating a specialized substrate and ALADS, offers superior precision for elemental analysis in edible salts.
• This technique is suitable for salt quality assessment, accurately quantifying key elements from ppm to wt% levels.
• The findings demonstrate a significant advancement in LIBS application for food analysis and quality control.