Quantitative determination of 26 aromatic amines derived from banned azo dyes in textiles through the use of LC, tandem MS, and identification of some structural isomers

Importance of the Topic

This study addresses the quantitation of 26 primary aromatic amines derived from banned azo dyes in textiles and leathers. These compounds are classified as carcinogenic under international regulations, and their strict control is essential for consumer safety and regulatory compliance. Monitoring amine levels helps textile manufacturers, testing laboratories, and regulatory bodies ensure that materials used in fashion and upholstery meet global safety standards.

Objectives and Study Overview

The primary goal was to develop a single liquid chromatography–tandem mass spectrometry (LC–MS/MS) method that:

• Minimizes sample clean-up to reduce analysis time and cost.
• Provides unequivocal identification and quantitation of 26 target aromatic amines.
• Separates structural isomers effectively, avoiding false positives.

The method was validated according to international textile and leather testing standards, aiming to replace or complement traditional gas chromatography approaches.

Methodology and Instrumentation

Sample Preparation:

• Textile samples (excluding disperse dyes) were extracted following ISO 14362-1:2012.
• Leather samples used ISO 17234-1:2010 and ISO 17234-2:2010 protocols.
• Disperse-dyed fabrics received an initial chlorobenzene extraction.
• Internal standard (Anthracene-d10) was added at 10 mg/L.
• Extracts were filtered through regenerated cellulose filters prior to injection.

Instrumentation:

• Agilent 1200 HPLC with Poroshell 120 SB-C18 column (3.0 × 100 mm, 2.7 µm).
• Agilent 6420 Triple Quadrupole mass spectrometer in positive electrospray ionization mode.

Chromatographic Conditions:

• Gradient elution with 0.05 mM formic acid in water and 0.1% formic acid in acetonitrile.
• Flow rate: 0.6 mL/min; column temperature: 40 °C; run time: 12 min.
• Multiple reaction monitoring (MRM) transitions were optimized for each amine.

Main Results and Discussion

The optimized LC–MS/MS method achieved baseline separation of all 26 amines, including critical structural isomers such as various dimethylanilines and chlorinated anilines. Calibration curves over 0.1–5 mg/L exhibited excellent linearity (R2 ≥ 0.999), low limits of detection (0.3–3.2 µg/L), and precision with relative standard deviations below 7%. Recovery rates averaged above 85% across both textile and leather matrices. The rapid chromatographic run (12 min) and minimal clean-up make this approach highly suitable for high-throughput screening.

Benefits and Practical Applications

The method offers several advantages:

• Reduced sample preparation time compared to conventional GC/MS workflows.
• Reliable separation of isomeric amines to avoid regulatory false positives.
• Simultaneous screening and quantitation of all target analytes in a single run.
• Compliance with major regulations (REACH, GB 18401:2010, KC Mark).

This makes it well suited for industrial quality control, regulatory enforcement laboratories, and research institutions focusing on textile safety.

Future Trends and Opportunities

Advances may include:

• Integration with high-resolution mass spectrometry for broadened screening of unknown amines.
• Automation of sample preparation using solid-phase extraction cartridges to further reduce labor.
• Miniaturized LC–MS/MS platforms for on-site testing in manufacturing facilities.
• Extending the approach to related matrices such as plastics, footwear, and food packaging materials.

Conclusion

The developed LC–MS/MS protocol provides a fast, accurate, and cost-effective solution for the quantitative determination of banned aromatic amines in textiles and leathers. Its high sensitivity, robust isomer separation, and compliance with international standards position it as a valuable tool in ensuring material safety and regulatory adherence.

Reference

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3. Rapid analysis of aromatic amines in cigarette smoke by LC-ESI-MS/MS, Xie et al., Talanta, 2013.
4. Determination of 20 aromatic amines in food simulants by LC-ESI-MS/MS, Mortensen et al., Journal of Chromatography A, 2005.
5. Quantitative determination of 22 primary aromatic amines by cation-exchange SPE and LC-MS/MS, Aznar et al., Journal of Chromatography A, 2009.