Analysis of the Release of N-Nitrosamines from Rubber Teats and Soothers

Importance of the Topic

N-nitrosamines are recognized carcinogenic compounds that can migrate from rubber materials into food and saliva simulants, posing health risks especially for infants. Ensuring accurate detection and quantification of these analytes in baby bottle teats and soothers is critical for regulatory compliance and product safety assessment.

Objectives and Overview of the Study

This study presents a simple and reliable analytical method for the identification and quantification of twelve N-nitrosamines released from rubber teats and soothers. The goal is to establish method sensitivity, linearity, repeatability, and low detection limits using gas chromatography coupled with a nitrogen chemiluminescence detector (GC/NCD).

Methodology and Instrumentation

• Instrumental setup: Agilent 8890 GC with multimode inlet (MMI) and 8255 NCD in nitrosamine mode.
• Column: Agilent J&W DB-WAX, 30 m × 0.53 mm, 1 µm film thickness; helium as carrier gas, constant flow.
• Inlet programming: splitless injection, initial 150 °C ramped to 250 °C for optimal volatilization and minimal thermal degradation.
• Detection parameters: burner at 450 °C, oxidizer (O₂) flow 5 mL/min, ozone generator on, vacuum pump on; nitrosamine mode avoids hydrogen flow.
• Standards and calibration: 12-component nitrosamine mix and N-nitrosodiisopropylamine (NDiPA) as internal standard; calibration range 50–1 000 µg/L.
• Sample preparation: migration test in nitrite-containing artificial saliva at elevated temperature, extraction with dichloromethane, solvent evaporation under light-protected conditions.

Main Results and Discussion

Optimization of inlet temperature (150 °C initial) balanced volatility and stability, while nitrosamine detector mode enhanced peak response compared to standard mode. Oxygen flow of 5 mL/min delivered higher sensitivity. Baseline separation was achieved for most analytes; NEPhA and NMPhA exhibited partial coelution at low concentrations. Calibration curves yielded correlation coefficients (R²) ≥ 0.9962, with retention time RSD ≤ 0.07% and area RSD ≤ 2.8%. Practical limits of detection were 10 µg/L for early eluting compounds and 25 µg/L for late eluters. Real sample testing demonstrated superior selectivity of NCD over mass spectrometry, with minimal interference in a commercial rubber teat extract.

Benefits and Practical Applications of the Method

• High sensitivity and selectivity for N-nitrosamines without hydrocarbon interferences.
• Robust quantification with low detection limits suitable for regulatory monitoring.
• Reproducible performance supports routine QC testing in manufacturing and compliance labs.
• Simple sample preparation aligns with international standards (BS EN 12868, GB 28482, SN/T 4451).

Future Trends and Opportunities

Integration of GC–triple quadrupole MS offers enhanced confirmation and structural elucidation for complex matrices. Advances in detector technologies and data processing algorithms may enable lower detection limits and faster runtimes. Continued method adaptation for diverse food contact materials and automated on-line sampling could improve throughput and regulatory compliance.

Conclusion

The developed GC/NCD method provides a reliable, sensitive, and selective approach for monitoring N-nitrosamines released from rubber teats and soothers. It meets stringent regulatory criteria, delivers excellent repeatability and linearity, and is well suited for quality assurance and safety testing in infant care products.

References

1. BS EN 12868:2017 Child Use and Care Articles – Determination of the Release of N-nitrosamines and N-nitrosatable Substances from Elastomer or Rubber Teats and Soothers.
2. China National Standard GB 28482-2012 Safety Requirements of Soothers for Babies and Young Children.
3. China National Standard SN/T 4451-2016 Determination of Migration of N-nitrosamines in Child Feeding Nipples – GC/MS.
4. Agilent OpenLab CDS Data Analysis Reference Guide.