WCPS: Direct Metal Analysis by New Galvano-Mirror fs-LA-ICP-MS using 100%-Normalization Method with NIST 612 Glass CRM as Calibration Standard

Significance of the Topic

Quantitative solid analysis by laser ablation ICP-MS is critical when conventional dissolution is impractical. Calibration challenges arise from the lack of matrix-matched standards. Combining a 100% normalization approach with a femtosecond laser system compensates for varied ablation yields and minimizes elemental fractionation, enabling precise multi-element determination in metals and alloys.

Objectives and Study Overview

This work evaluates a novel LA-ICP-MS calibration strategy:

• Implement a 100% normalization method using NIST 612 glass as a universal calibration standard.
• Utilize a galvano-mirror femtosecond laser to reduce elemental fractionation.
• Validate quantification accuracy on a set of metal certified reference materials (CRMs).

Methodology and Instrumentation

• Calibration Standard: NIST SRM 612 Trace Elements in Glass, with consensus values for ~40 elements.
• Femtosecond LA System: RAIJINα featuring galvano-mirror scanning, 290 fs pulse width at 257 nm, 20 kHz repetition, 10 µm spot size, raster pattern.
• ICP-MS: Agilent 8900 Triple Quadrupole (ICP-QQQ) with MassHunter software’s 100% normalization routine.
• Samples: BAM 310 Al/Mg alloy, NIST 1249 Ni alloy, ERM-EB385 pure Cu; surfaces cleaned in 1% HNO₃.
• Corrections: Half-mass correction for 48Ti++ interference on 24Mg in NIST 1249; multi-tune lens detuning for high-abundance 63Cu.

Main Results and Discussion

• Element recoveries predominantly fell within 80–120%, covering trace to major concentrations.
• 100% normalization effectively compensated for ablation yield differences between glass and metal matrices.
• Femtosecond ablation yielded particles representative of the bulk, reducing fractionation relative to nanosecond lasers.
• Half-mass correction improved Mg accuracy in the Ti-bearing Ni alloy.
• Multi-tune lens detuning prevented detector overload, enabling accurate 63Cu quantification.

Benefits and Practical Applications

• Eliminates need for matrix-matched solid standards, simplifying calibration workflows.
• Avoids dissolution, saving time, reagents, and reducing contamination risk.
• Applicable to a wide range of conducting and non-conducting materials, including alloys and ceramics.
• Supports quality control, alloy development, and forensic analysis in research and industry.

Future Trends and Potential Applications

• Extension of normalization techniques to other non-matched standards and complex matrices.
• Further optimization of fs-LA parameters for ultra-trace isotopic analysis.
• Integration with spatially resolved imaging for heterogeneous samples.
• Development of automated, AI-enhanced calibration workflows within LA-ICP-MS platforms.

Conclusion

The fusion of galvano-mirror femtosecond LA with the 100% normalization protocol and NIST 612 glass standard offers a robust, accurate, and streamlined approach for quantitative LA-ICP-MS. This method overcomes traditional calibration barriers, broadens material applicability, and enhances operational efficiency.

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