LC/MS/MS Analysis of Alkylphenol Ethoxylates (APEO) and Alkylphenols (AP)

Significance of the Topic

Alkylphenol ethoxylates (APEOs) and their degradation products pose significant environmental and health concerns due to endocrine disrupting properties. In the textile industry, these surfactants are restricted by global regulations such as REACH and certification programs like OEKO-TEX.

Objectives and Overview

This study presents an LC–MS/MS method from the “Method Package for Restricted Chemicals in Textiles” to simultaneously analyze nonylphenol ethoxylates (NPEOs), octylphenol ethoxylates (OPEOs), and their corresponding alkylphenols (APs). The aim was to achieve sensitive, robust quantitation over a wide concentration range.

Methodology and Instrumentation

Analyses were performed on a Shimadzu LCMS-8045 triple quadrupole mass spectrometer. Key conditions:

• Column: Shim-pack FC ODS, 75 mm × 2.0 mm, 3 µm
• Mobile phases A/B: 10 mM ammonium acetate (pH 3.6)/acetonitrile for APEOs; water/acetonitrile for APs
• Gradient: 70 % B to 95 % B in 5 min for APEOs; 50 % B to 95 % B in 9 min for APs
• Flow rate: 0.25 mL/min (APEOs), 0.4 mL/min (APs)
• Injection: 5 µL for APEOs, 10 µL for APs
• Ionization: ESI positive for APEOs, ESI negative for APs

Main Results and Discussion

MRM transitions were optimized selecting [M+NH4]+ for APEOs and [M–H]– for APs. Both NPEOs (n = 3–16) and OPEOs (n = 3–15) showed linear calibration (1–100 ng/mL) with r2 > 0.998. AP compounds (NP, 4-n-NP, 4-n-OP, 4-t-OP) also yielded r2 > 0.994 under the modified mobile phase. Chromatograms demonstrated good peak resolution and reproducibility.

Benefits and Practical Applications

The method enables comprehensive screening of restricted nonionic surfactants and their degradation products in textiles, supporting compliance with global regulations. High sensitivity and wide linear range facilitate trace-level detection in quality control and environmental monitoring.

Future Trends and Potential Uses

Integration with high-throughput workflows and expansion to additional analyte classes (e.g. perfluorochemicals, azo dyes, aromatic amines) is anticipated. Advances in MS instrumentation may further lower detection limits and improve multiplexed analyses for next-generation safety testing.

Conclusion

The LC–MS/MS method from the Shimadzu method package provides reliable quantitation of APEOs and APs in textiles, meeting regulatory requirements with robust linearity (1–100 ng/mL). Its adaptability and sensitivity make it a valuable tool in industrial and environmental analytics.

Reference

• Lee J.X., Xing J., Chia S.H., Zhan Z., ASMS 2018, Poster Session WP 779.