Quantitative Analysis of Fluorine ( 9F) by EDXRF

Quantitative Analysis of Fluorine by EDXRF

Significance of the Topic

Fluorine-containing compounds are widely used due to properties such as flame retardance, water repellency and heat resistance. Environmental concerns including global warming, ozone depletion and bioaccumulation have driven regulatory action and the development of safer alternatives. Reliable quantitation of fluorine is thus critical for product development and quality control.

Objectives and Study Overview

This application note presents two case studies using EDXRF for fluorine analysis: quantitation of fluorinated water-repellent finish on fabric and determination of detection limits and precision for fluorine in resin films and powders.

Methodology and Instrumentation

The analyses were performed on a Shimadzu EDX-800HS equipped with a rhodium-target X-ray tube operating at 15 kV, Si(Li) detector in vacuum, and no primary filter. Integration times were 400 s for fabric and resin film, and 300 s for powder samples. Calibration curves were built using standard samples with known fluorine content.

Main Results and Discussion

Case 1 – Water-repellent Fabric

• Fabric treated with 5.3 g/m2 fluoropolymer (100 g/m2 nominal input) formed a 1–1.3 µm film.
• Calibration using standards of 1%, 3%, 7% and 14% produced an accuracy of 0.052%.
• Unknown sample measured at 4.68% fluorine finish with 0.15% standard deviation (3.2% CV).

Case 2 – Resin Film Thickness

• Fluorine film thickness from 0 µm to ~5 µm showed linear X-ray intensity correlation.
• Lower detection limit of 2.0 µm and upper quantitation limit of 2.7 µm for CF2 films.

Case 3 – Powder Analysis

• Briquettes prepared from cellulose mixed with LiF standards at 0 ppm, 2 500 ppm, 5 000 ppm.
• Quantitation down to 500 ppm detection limit and 84 ppm accuracy at 300 s integration.
• Repeatability test at 5 000 ppm gave mean 5 066 ppm, standard deviation 182.6 ppm, CV 3.6%.

Practical Benefits and Applications

EDXRF enables non-destructive, rapid analysis of fluorine in solids and thin films without complex sample prep. It supports quality control in textiles, polymer coatings, food and pharmaceutical matrices where fluorine levels must be tightly monitored.

Future Trends and Opportunities

Emerging applications include on-line monitoring of fluorination processes, integration with micro-XRF for spatial mapping and improved detection of light elements in heavy matrices through enhanced detector technology and AI-driven spectrum interpretation.

Conclusion

The EDX-800HS system demonstrates high sensitivity and precision for fluorine quantitation across diverse sample types. Detection limits down to 500 ppm in powders and reliable film thickness measurement support rigorous QA/QC in industrial and research settings.

References

No specific literature references were provided in the original document.