ISO 10280:1991

Overview

ISO 10280:1991 - "Steel and iron - Determination of titanium content - Diantipyrylmethane spectrophotometric method" is an International Standard that specifies a laboratory spectrophotometric procedure to determine titanium content in steels and irons. First published in 1991, the method uses 4,4'-diantipyrylmethane to form a yellow coloured complex with Ti, measured spectrophotometrically at about 385 nm. The procedure is applicable to titanium levels from 0.002 % to 0.80 % (m/m).

Key topics and technical requirements

• Analytical range: 0.002–0.80 % Ti (m/m).
• Chemical principle: Formation of a yellow Ti–diantipyrylmethane complex followed by spectrophotometric measurement (~385 nm).
• Sample preparation: Acid digestion (HCl, HNO3, H2SO4), fusion of residues with potassium hydrogen sulfate (KHSO4), treatment of insoluble residue (HF and tartaric acid), and special fusion with sodium carbonate for tungsten-containing samples.
• Reagents and quality: Use analytical-grade reagents and ISO‑3696 grade 2 water; defined reagent solutions include diantipyrylmethane, titanium standards (stock and working), iron solution, ammonium oxalate, ascorbic and tartaric acid solutions.
• Apparatus: Class A volumetric glassware and a spectrophotometer with wavelength accuracy ±2 nm and absorbance repeatability ±0.003 in the 0.05–0.85 range.
• Calibration and calculation: Calibration graph of net absorbance vs. µg Ti/mL; explicit procedures for preparing calibration solutions and converting net absorbance to % Ti. A compensating solution and blank procedure are specified.
• Precision: Interlaboratory trial data (17 laboratories) and repeatability/reproducibility statistics are reported; a logarithmic relationship between Ti content and precision is given.

Practical applications

• Routine quality control and chemical analysis in steel mills and foundries to verify titanium additions or impurity levels.
• Metallurgical laboratories performing certification of steel and iron chemical composition.
• Materials testing laboratories that require reliable Ti quantification for process control, alloy specification compliance, failure analysis, or research.

Who should use this standard

• Analytical chemists and technicians in steel/iron production and third‑party testing labs.
• Quality assurance managers in metallurgy and materials procurement.
• Laboratories implementing validated spectrophotometric methods for elemental analysis.

Related standards

ISO 10280 references and aligns with other ISO documents for sampling and laboratory practice, including:

• ISO 377‑2 (sampling of wrought steels),
• ISO 3696 (water for analytical use),
• ISO 385‑1, ISO 648, ISO 1042 (laboratory glassware),
• ISO 5725 (precision of test methods - repeatability and reproducibility).

Keywords: ISO 10280:1991, titanium determination, diantipyrylmethane, spectrophotometric method, steel and iron analysis, Ti content, spectrophotometer, laboratory method.