Determination of the N-Nitrosamine Content in Rubber Articles Using the Agilent 7000A Triple Quadrupole GC/MS System

Importance of the Topic

N-nitrosamines are potent carcinogens formed during rubber manufacture and storage. Their presence in consumer products such as food contact materials and infant pacifiers is regulated by authorities (EU max 10 µg/kg; US FDA max 10 µg/kg). Accurate, trace-level quantification in complex matrices is therefore critical for consumer safety and regulatory compliance.

Study Objectives and Overview

This application note describes the development and validation of a triple quadrupole GC/MS multiple reaction monitoring (MRM) method for determining seven common N-nitrosamines (NDMA, NDEA, NDBA, NPIP, NPYR, NMOR, NEPhA) in rubber articles. Key goals included achieving low detection limits, high linearity, and reliable recoveries in real sample matrices.

Methodology and Instrumentation

Sample preparation involved cutting rubber articles into small pieces, Soxhlet extraction in dichloromethane at 55 °C, distillation cleanup and dilution to 2 mL in n-hexane. Calibration standards (25–500 µg/L) containing an internal standard (NDPA) were prepared in n-hexane.

Instrumentation Used

The analytical system comprised an Agilent 7890A gas chromatograph with splitless injection, an Agilent J&W DB-624 capillary column (30 m × 0.25 mm × 1.4 µm), and an Agilent 7000A Triple Quadrupole mass spectrometer with electron impact ionization in MRM mode. Optimized GC temperature program and MRM transitions enabled baseline separation and high sensitivity for all analytes.

Main Results and Discussion

All seven N-nitrosamines exhibited excellent chromatographic resolution (except slight NDMA tailing) and linear calibration (R² > 0.998). Method detection limits ranged from 0.39 to 1.86 µg/kg, well below regulatory thresholds. Matrix spike recoveries at 10 µg/kg averaged 70–82% with RSDs below 7.6%, demonstrating method accuracy and precision in complex rubber matrices.

Benefits and Practical Applications of the Method

• High selectivity and sensitivity for trace N-nitrosamine analysis
• Compliance with EU and FDA regulatory limits
• Robust performance in challenging sample matrices
• Rapid screening and confirmation using MRM

Future Trends and Applications

Emerging directions include automated, high-throughput sample preparation, expansion to new consumer and environmental matrices, integration of high-resolution MS for enhanced specificity, and the use of data-driven algorithms to streamline quantitative analysis and regulatory reporting.

Conclusion

The described triple quadrupole GC/MS MRM method provides a reliable, sensitive, and regulatory-compliant approach for quantifying trace N-nitrosamines in rubber articles, supporting quality control and consumer safety monitoring.

Reference

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2. Child use and care articles – Methods for determining N-nitrosamines and N-nitrosatable substances from elastomer or rubber teats and soothers. EN 12868:1999.
3. Glória M, A. B. N-Nitrosamines in baby bottles and pacifiers. Ciência e Cultura. 1991;43:44–47.
4. Vieira ER. Determination of N-nitrosamines and N-nitrosatable substances in rubber teats and soothers by GC-TEA. Braz Arch Biol Technol. 2006;49(special):73–77.