High-Speed X-Ray Diffraction Analysis of Asbestos (Chrysotile) Using Wide-Range High-Speed Detector "OneSight"

Significance of the Topic

Asbestos, especially chrysotile, has been historically used in construction for its heat and chemical resistance. However, health risks have led to strict regulatory limits on asbestos content, typically below 0.1% by weight. X-ray diffraction (XRD) is the official method for quantitative asbestos analysis in many regions, including Japan. Rapid and sensitive detection methods are essential for regulatory compliance and occupational safety.

Study Objectives and Overview

The aim of this work was to demonstrate a high-speed quantitative XRD method for chrysotile asbestos using Shimadzu’s new wide-range, high-speed detector OneSight. The study outlines sample preparation, measurement protocols, and performance evaluation against conventional scintillation detectors.

Methodology

The quantitative analysis followed the standard absorption correction method:

• Asbestos samples were treated with formic acid and collected on a filter.
• The filter was placed on a zinc (Zn) base standard plate.
• XRD measurements were performed at the chrysotile peak and the Zn peak, each with a 120-second integration time.
• The transmitted Zn diffraction intensity from a blank filter was used to calculate a correction coefficient for each sample.
• Corrected peak intensities were plotted against known chrysotile masses to generate a calibration curve.

Used Instrumentation

This analysis employed:

• XRD-6100 diffractometer with Cu target X-ray tube (40 kV, 30 mA) and Ni filter monochromation.
• OneSight wide-range, high-speed semiconductor detector array (> 1000 channels) operated in “One Shot” mode.
• Shimadzu proprietary filter holder and rotation sample attachment for environmental quantitative analysis.

Main Results and Discussion

Calibration covered sample masses from blank to 5 mg of chrysotile. A third-order polynomial fit (Q = A·I³ + B·I² + C·I + D) yielded a correlation coefficient of 0.9950. The lower limit of detection (LoD) achieved with OneSight was 0.0034 mg and the lower limit of quantitation (LoQ) was 0.0102 mg with 120 s integration. In contrast, a conventional scintillation detector required 1000 s to reach LoD = 0.0045 mg and LoQ = 0.0135 mg. Thus, the OneSight detector provided comparable or better sensitivity in one-eighth the time.

Benefits and Practical Applications

The high-speed OneSight detector enables:

• Rapid compliance testing under JIS A 1481-3 guidelines.
• Increased sample throughput in QA/QC and environmental monitoring.
• Reduced measurement time and operational costs.

Future Trends and Potential Applications

Advances may include integration of OneShot mode into automated workflows, extension to other regulated minerals or phases, and further improvements in detector sensitivity and dynamic range. Real-time monitoring of airborne fibers or in-line process control are promising directions.

Conclusion

Shimadzu’s OneSight wide-range, high-speed detector provides a fast, sensitive, and reliable XRD method for quantitative analysis of chrysotile asbestos. Measurement times can be reduced from 1000 s to 120 s while maintaining or improving detection limits, facilitating regulatory compliance and laboratory efficiency.

References

• Shimadzu Application Note No. X257: High-Speed X-Ray Diffraction Analysis of Asbestos (Chrysotile) Using Wide-Range High-Speed Detector OneSight, First Edition August 2014.