Overview
ISO 4192:1981 specifies a flame atomic absorption spectrometric (AAS) method for the determination of lead (Pb) in aluminium and aluminium alloys. The method covers products with lead contents between 0.01 % and 1.5 % (m/m) and defines the principle, required reagents and apparatus, sampling, analytical procedure, expression of results and the content of the test report.
Keywords: ISO 4192, lead content determination, aluminium alloys, flame atomic absorption spectrometry, AAS lead determination.
Key Topics and Requirements
- Analytical principle: Nebulization of a dissolved aluminium sample into an air–acetylene flame and measurement of Pb absorption at characteristic resonance lines (typically near 217.0 nm or 283.3 nm) using a lead hollow‑cathode lamp.
- Reagents: Use analytical‑grade acids and high‑purity water. Typical reagents include nitric acid (HNO3), hydrochloric acid (HCl) mixture for dissolution, and hydrofluoric acid (HF) when silica/silicon residues are present. Certified lead standard solutions are used for calibration.
- Apparatus: Flame AAS instrument with air‑acetylene burner, Pb hollow‑cathode lamp, burette for volumetric additions, and standard laboratory glassware.
- Sampling: Laboratory samples are prepared from chips (≤ 1 mm thickness) obtained by machining (milling or drilling) to ensure representativity.
- Calibration and blanks: Establish calibration curves across the target range using prepared lead standards; run reagent blanks in parallel and apply blank corrections to measured absorbances.
- Procedure notes: The standard prescribes controlled dissolution of the test portion, removal of nitrous fumes by boiling, appropriate dilution to specified volumes, filtration/incineration where insoluble silicon residues occur, and consistent nebulization during measurements.
- Results expression: Lead content is reported as mass percent (m/m), calculated from the measured mass of Pb in the test solution, corrected for blank and dilution factors. The test report must include sample identification, method reference, results, and any deviations or special operations.
Applications and Who Uses It
- Quality control and specification testing in aluminium smelters, alloy manufacturers, foundries and downstream fabricators.
- Analytical and metallurgical laboratories performing compliance testing, incoming inspection of raw materials, or alloy certification.
- Environmental and regulatory laboratories assessing lead levels in aluminium products where Pb content influences recycling, safety, or mechanical properties.
Related Standards
- ISO 4192 is part of the suite of ISO methods maintained under technical committee ISO/TC 79 (Metals, ferrous and non‑ferrous). Users should also consult current ISO standards on sampling of aluminium and alloys and other accredited methods for metal analysis to ensure full compliance with testing and reporting requirements.