High Sensitive and Accurate Analysis of Nitrosamines Using GC/MS/MS

Significance of the Topic

Trace-level nitrosamines have emerged as critical analytes in pharmaceutical quality control following the detection of carcinogenic N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) in valsartan products in 2018. These compounds are classified as probable human carcinogens by IARC and are regulated under ICH M7 guidelines. Robust analytical methods are therefore essential to ensure patient safety and regulatory compliance.

Objectives and Study Overview

This study presents a simultaneous analytical protocol for five nitrosamines (NDMA, NDEA, NEIPA, NDIPA and NDBA) in drug substances using a Shimadzu GCMS-TQ8050 NX triple quadrupole GC/MS/MS system. The goal was to achieve high sensitivity, accuracy and reproducibility across a wide dynamic range while minimizing matrix interferences.

Methodology

• Calibration standards: Ten‐point curve from 0.2 to 200 ng/mL in dichloromethane.
• Sample preparation: 0.1 g drug substance extracted with 5 mL dichloromethane, vortex-mixed, centrifuged and filtered. Spiked extracts at 0.5, 5 and 50 ng/mL to evaluate matrix effects.
• Quantitation: Multiple reaction monitoring (MRM) with two transitions per analyte and optimized collision energies.

Used Instrumentation

• Gas chromatograph–mass spectrometer: GCMS-TQ8050 NX
• Autosampler: AOC-20i+s Plus
• Column: SH-I-624Sil MS (30 m × 0.25 mm I.D., 1.4 μm film)
• Injection: Splitless at 250 °C, 2 μL, high‐pressure for 1.5 min at 250 kPa
• Carrier gas: Helium, linear velocity 39.7 cm/s
• Oven program: 50 °C (1 min) → 20 °C/min → 250 °C (3 min)
• MS conditions: Interface 250 °C, ion source 230 °C, EI ionization, unit resolution Q1–Q3

Main Results and Discussion

• Linearity: All calibration curves exhibited correlation coefficients (R) ≥ 0.999 and R² ≥ 0.998.
• Reproducibility: Area %RSD ≤ 8 % across calibration points (0.2–200 ng/mL).
• Matrix effects: Spiked sample/standard area ratios ranged from 75 % to 106 %, confirming minimal suppression or enhancement.
• Spiked sample repeatability: %RSD ≤ 10 % for all analytes and concentration levels in five types of drug substances.

Practical Benefits and Applications

• Enables reliable trace‐level quantitation of nitrosamines in active pharmaceutical ingredients (APIs) and excipients.
• MRM mode eliminates matrix interferences, improving selectivity in complex drug matrices.
• High throughput and reproducibility support routine QA/QC and regulatory testing in pharmaceutical laboratories.

Future Trends and Opportunities

• Application of high‐sensitivity LC/MS/MS workflows for polar nitrosamines and non-volatile analogs.
• Integration of automated sample preparation and on‐line cleanup to further reduce matrix effects.
• Adoption of high-resolution accurate mass spectrometry (HRAM) for enhanced selectivity and identification of unknown nitrosamine derivatives.

Conclusion

The Shimadzu GCMS-TQ8050 NX platform provides a robust, sensitive and accurate method for the simultaneous determination of five nitrosamines in pharmaceutical substances. Excellent linearity, reproducibility and minimal matrix effects demonstrate its suitability for compliance with ICH M7 guidelines and routine quality control.

References

• International Council for Harmonisation (ICH) M7 (R1): Addendum on Assessment and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals to Limit Potential Carcinogenic Risk.