Analysis of N-Nitrosodimethylamine and N-Nitrosodiethylamine Using the Agilent 7697A Headspace Sampler, 8890/5977 GC/MSD System

Importance of the Topic

Hypertension affects over one billion adults worldwide, and angiotensin II receptor blockers (sartans) are a primary treatment. Recent contamination incidents involving probable carcinogenic nitrosamines, N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), underscore the need for reliable impurity analysis to ensure patient safety and regulatory compliance.

Objectives and Study Overview

This application note demonstrates the use of an Agilent 8890 GC equipped with a 7697A headspace sampler and a 5977 GC/MSD to quantify NDMA and NDEA in sartan drug products in accordance with US FDA guidance. It compares performance to previous methods, establishes detection limits, and validates calibration, reproducibility, and recovery in real sample matrices.

Applied Methodology and Instrumentation

Standards of NDMA and NDEA were prepared in high-purity N-methyl-2-pyrrolidinone (NMP) and calibrated across 0.025 to 100 μg. Samples included neat standards and matrix spikes in dissolved valsartan tablets.

Instrumentation and key parameters:

• 7697A Headspace Sampler: oven at 130 °C, loop at 180 °C, transfer line at 185 °C, 15 min equilibration, 1 min injection from 20 mL vials with agitation.
• 8890 GC: split mode (5:1) with helium carrier, inlet at 220 °C, fast-rate oven program (40 °C hold, ramp to 160 °C at 20 °C/min, then to 240 °C at 10 °C/min; total cycle 16.5 min) on a DB-1701 column (30 m×250 μm×1.0 μm).
• 5977 GC/MSD: extractor source at 230 °C, quadrupole at 150 °C, SIM at m/z 74 for NDMA and m/z 102 for NDEA.

Main Results and Discussion

Chromatographic separation yielded distinct peaks at 5.80 min for NDMA and 7.25 min for NDEA. Calibration curves over 0.025–0.5 μg were linear with R² ≥ 0.999 and inverse weighting. The LOQ values met FDA criteria at 0.10 ppm for NDMA and 0.05 ppm for NDEA, with LOD demonstrated at 0.025 μg on-column. Reproducibility tests (n=5) showed relative standard deviations below 7 % at low levels and below 3 % at mid-range. Matrix spike recoveries at target LOQs were within acceptable ranges, confirming method robustness in sartan formulations.

Benefits and Practical Application of the Method

This workflow delivers high sensitivity and specificity for trace nitrosamine monitoring, ensuring compliance with regulatory limits. The headspace GC/MS approach enables minimal sample preparation, efficient throughput, and compatibility with existing laboratory infrastructure for routine quality control.

Future Trends and Opportunities for Application

Enhancements may include optimization for lower-purity solvents, adaptation to ultra-fast GC platforms to reduce cycle times, expansion to additional nitrosamine analogs, and integration of advanced data analytics for automated reporting.

Conclusion

The Agilent 8890 GC coupled with the 7697A headspace sampler and 5977 GC/MSD provides a reliable, FDA-compliant method for detecting NDMA and NDEA in sartan products, combining rapid analysis with robust sensitivity and reproducibility.

References

1. Global Health Observatory data. World Health Organization.
2. Blood Pressure UK: high blood pressure prevalence.
3. Barreras A., Gurk-Turner C. Angiotensin II Receptor Blockers. Proc Bayl Univ Med Cent. 2003;16(1):123–126.
4. GC/MS Headspace Method for Detection of NDMA in Valsartan Drug Substance and Drug Products. U.S. Food and Drug Administration, FY18-176-DPA-S.
5. European Medicines Agency. Report of NDEA in sartan products.
6. Combined NDMA and NDEA Impurity Assay by GC/MS Headspace. U.S. FDA, FY19-005-DPA-S.