Analysis of Pb in gasoline according to ASTM D5059 norm with ARL PERFORM'X Sequential X-Ray Fluorescence Spectrometer

Importance of the topic

Monitoring trace levels of lead in gasoline remains critical for environmental compliance, engine performance and public health protection. Accurate lead quantification ensures adherence to stringent regulatory limits and supports quality control in petrochemical production.

Objectives and Overview of the Study

This study evaluates the performance of the Thermo Scientific ARL PERFORM’X sequential X-ray fluorescence (XRF) spectrometer for low-level lead determination in gasoline, following ASTM D5059 Test Method C. Five calibration standards were prepared with known lead concentrations and bismuth was used as an internal standard.

Methods and Instrumentation

A 4200 W ARL PERFORM’X system equipped with a 5GN+ Rh tube (50 µm Be window) and helium purge was employed. Key analytical settings:

• Tube voltage: 60 kV
• Tube current: 50 mA (3 kW power to minimize mylar film heating)
• Detector: Scintillator
• Collimator: Fine
• Crystal: LiF200
• Measured lines: Bi Lα1 (internal standard), Pb Lα1 and Pb background

Liquid samples were loaded safely using the LoadSafe design with liquid cassette recognition and helium shutter protection to ensure stable and reproducible measurements.

Main Results and Discussion

The calibration curve constructed from five standards spanning 0.1 to 19.4 ppm Pb exhibited excellent linearity. The standard error of estimate was 0.4 ppm. Repeatability tests on two samples (A: ~3.7 ppm Pb, SD 0.02; B: ~10.3 ppm Pb, SD 0.2) confirmed high precision and reproducibility.

Benefits and Practical Applications

• Rapid, non-destructive analysis with minimal sample preparation
• High throughput and automated loading for routine quality control
• Accurate low-level detection suitable for meeting regulatory standards
• Robust performance under helium atmosphere reducing spectral interferences

Future Trends and Possibilities

Further improvements may include integration of automated sample changers, development of portable XRF units for field screening, extension to other trace elements and incorporation of machine-learning algorithms for real-time data correction and enhanced detection limits.

Conclusion

The ARL PERFORM’X XRF spectrometer, operated under ASTM D5059 Test Method C, delivers accurate, precise and reproducible lead measurements in gasoline. Its advanced safety and automation features make it an excellent choice for routine petrochemical analysis.

Reference

• Thermo Fisher Scientific, Application Note AN41675: Analysis of Pb in gasoline to ASTM D5059 with ARL PERFORM’X Sequential X-Ray Fluorescence Spectrometer.
• ASTM International, ASTM D5059: Standard Test Method for Lead in Gasoline by Sequential X-Ray Fluorescence Spectrometry.