Test Methods for Certain Aromatic Amines Derived from Azo Colorants

Significance of the Topic

Azo colorants are widely used organic pigments that can degrade into aromatic amines with carcinogenic potential under skin contact, microbial action and metabolic processes. Regulatory bodies in the EU, China, South Korea and Japan have imposed restrictions on these compounds in textiles and leather goods to protect consumer health.

Objectives and Study Overview

This study outlines standardized test methods for the detection and quantification of specific aromatic amines derived from azo colorants. It reviews the analytical workflow defined in EN 14362-1 and EN 14362-3 and highlights the requirements for confirming the presence of hazardous amines such as 4-aminoazobenzene.

Methodology and Instrumentation

Textile samples are collected and their fiber composition and dyeing processes evaluated. Colorants are extracted where necessary and subjected to reductive cleavage to release aromatic amines. The resulting amines are purified and concentrated prior to analysis by gas chromatography–mass spectrometry. Positive detections are further verified using high-performance liquid chromatography with PDA detection to eliminate false positives.

Used Instrumentation

• Gas Chromatograph–Mass Spectrometer: Shimadzu GCMS-QP2020
• Capillary Column: VB-35 (35% phenyl–methylpolysiloxane, 30 m × 0.25 mm I.D., 0.25 μm film)
• Injection Conditions: 1 μL split injection (8:1) at 240 °C
• Oven Program: 100 °C (1 min) ramp 20 °C/min to 300 °C (3 min)
• Carrier Gas: Helium at 37.2 cm/sec

Main Results and Discussion

Chromatograms of standard mixtures demonstrate distinct retention times and characteristic m/z signals for target amines, including aniline, 1,4-phenylenediamine and 4-aminoazobenzene. The GC-MS method based on EN 14362-1 can detect common amines but requires EN 14362-3 for reliable identification of 4-aminoazobenzene. Detection limits and recovery rates vary with the dye matrix and sample preparation.

Benefits and Practical Applications

This validated workflow enables routine screening and compliance testing of textiles and leather goods in regulatory and industrial laboratories. The dual-stage analysis minimizes false positives and ensures adherence to international standards, supporting quality assurance and consumer safety initiatives.

Future Trends and Potential Applications

Emerging techniques such as HPLC-MS and capillary electrophoresis–MS offer enhanced sensitivity and faster analysis times. Integration with automated sample preparation and data processing systems is expected to streamline high-throughput testing.

Conclusion

The described GC-MS based method, supported by confirmatory HPLC analysis, provides a robust approach for detecting carcinogenic aromatic amines from azo colorants. Adoption of standardized protocols ensures reliable compliance testing and protection of public health.

References

• EN 14362-1:2012 Textiles. Methods for determination of certain aromatic amines derived from azo colorants. Detection of the use of certain azo colorants accessible with and without extracting the fibres
• EN 14362-3:2012 Textiles. Methods for determination of certain aromatic amines derived from azo colorants. Detection of the use of certain azo colorants which may release 4-aminoazobenzene
• JIS L1940 Textiles. Regulation of certain aromatic amines derived from azo colorants in textile products
• ISO 17234-1:2015 Leather goods. Detection of certain aromatic amines derived from azo colorants. Screening method
• ISO 17234-2:2011 Leather goods. Detection of certain aromatic amines derived from azo colorants. Analytical method