Quantitative Analysis of Lead in Bismuth Bronze - Matrix Elements/Profile Correction and Comparison with AA

Význam tématu

Accurate determination of trace lead in bismuth‐bronze alloys is critical for environmental compliance such as RoHS. X‐ray fluorescence (XRF) offers rapid non‐destructive analysis, but spectral overlap between Pb and coexisting elements like Bi and Se limits quantitation at low concentrations. Implementing overlap and profile corrections expands XRF capability for both flat and irregularly shaped samples.

Cíle a přehled studie

This study evaluates quantitative XRF methods for measuring low‐level Pb in bismuth bronze. It compares results from flat‐surface ingots and cutting chips against atomic absorption (AA) analysis. Key goals include assessing calibration strategies, overlap correction for matrix elements, profile correction via internal standards, and repeatability under practical sample conditions.

Použitá metodika a instrumentace

Sample Preparation and Calibration

• Flat‐surface samples: Lathe cutting, ultrasonic cleaning (ethanol), calibration with five certified standards (Pb, Bi, Se).
• Chip samples: Cutting chips, arranging under 5 µm polypropylene film, ultrasonic cleaning, internal standard correction using Rh scattered radiation.

Overlap Correction

• Matrix element (dj) method applied to Pb using Bi and Se coexisting elements to address spectral overlap.

Profile Correction

• Internal standard (RhKα) normalization for cutting chips to correct irregular geometry.

Instrumentation

• EDX‐8000/7000: SDD detector, Rh target X‐ray tube, analytical lines PbLβ1, BiLα, SeKα, profile correction mode, measurement in air.
• AA‐7000: Wavelength 283.3 nm, slit 0.7 nm, current 10 mA, D2 background correction.

Hlavní výsledky a diskuse

Flat‐surface calibration yielded Pb accuracy of 0.0029 wt% and LOD 0.0015 wt%. Static repeatability for Pb showed CV 3.2%. Chip analysis achieved 0.0038 wt% accuracy and 0.0018 wt% LOD, with Pb CV between 1.1% and 3.9%. Comparison with AA revealed EDX errors under 10% (AA under 5%), demonstrating acceptable precision for monitoring requirements. Overlap and profile corrections effectively compensated for matrix interferences and sample geometry.

Přínosy a praktické využití metody

• Rapid, non‐destructive quantitation of Pb in bismuth bronze alloys.
• Minimal sample preparation for irregular chips without acid dissolution.
• Compliance monitoring for RoHS and other environmental regulations.

Budoucí trendy a možnosti využití

Future developments may include advanced detector technology to lower detection limits further, automated sample handling for high throughput, and adaptation of correction algorithms to other alloy systems. Integration with chemometric tools can enhance separation of overlapping spectra and streamline QA/QC workflows.

Závěr

Overlap correction for coexisting Bi and Se, combined with profile correction via an internal Rh standard, enables reliable Pb quantitation in both flat and chip‐form bismuth bronze samples. The methods support efficient, accurate XRF analysis for environmental compliance and industrial quality control.

Reference

1. Shimadzu Application News No. X246
2. Ochi H., Nakamura H., Watanabe S.: Advances in X‐Ray Chemical Analysis, Japan, Vol. 38, p.191 (2007)