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

Significance of Nitrosamine Analysis

In 2018, detection of NDMA and NDEA above permitted levels in valsartan triggered global regulatory concerns for nitrosamine contaminants in pharmaceuticals. These compounds are classified as probable human carcinogens by IARC and controlled as class 1 impurities under ICH M7 guidelines. Reliable trace-level detection of nitrosamines is critical for drug safety and quality control.

Study Objectives and Overview

This study presents a simultaneous quantitative analysis of five nitrosamines using a triple quadrupole GC/MS/MS system. The aim is to achieve high sensitivity, accurate quantitation, and minimal matrix interference in raw drug substances.

Methodology and Sample Preparation

Sample preparation involved 10-point calibration standards of NDMA, NDEA, NEIPA, NDIPA and NDBA in dichloromethane spanning 0.2 to 200 ng/mL. Drug substance extracts were prepared by mixing 0.1 g API or insoluble materials with 5 mL dichloromethane, followed by vortex mixing, centrifugation, and PTFE filtration. Spiked extracts equivalent to 0.025, 0.25 and 2.5 ppm in solid samples were used to assess matrix effects.

Used Instrumentation

• Shimadzu GCMS TQ8050 NX triple quadrupole gas chromatograph mass spectrometer
• AOC 20i+s Plus autosampler
• SH-I-624Sil MS capillary column (30 m × 0.25 mm I.D., 1.4 μm film)
• Splitless deactivated liner with low wool insert

Analytical Conditions

• Injection 2 μL splitless at 250 °C, 250 kPa for 1.5 min
• Carrier gas linear velocity 39.7 cm/s
• Oven program: 50 °C (1 min) then 20 °C/min to 250 °C (3 min)
• Interface 250 °C, ion source 230 °C, EI ionization
• MRM transitions for each nitrosamine with optimized collision energies

Main Results and Discussion

Calibration curves for all five compounds showed excellent linearity (R ≥ 0.999). Repeatability across calibration points yielded area percent RSD below 8%. Matrix effect studies produced area ratios between 75% and 106%, indicating minimal interference. Spiked sample reproducibility remained within 10% RSD, confirming robust performance in diverse drug matrices.

Benefits and Practical Applications

• High sensitivity enables detection of nitrosamines at trace concentrations
• MRM acquisition effectively eliminates coeluting matrix interferences
• Superior reproducibility supports consistent QA/QC operations in pharmaceutical analysis

Future Trends and Potential Applications

Advances in detection technology and automation are expected to enhance throughput and sensitivity further. Integration of GC/MS/MS and LC/MS/MS workflows may expand analysis to highly polar nitrosamines. Evolving regulatory requirements will continue to drive the adoption of robust trace analysis techniques for pharmaceutical quality assurance.

Conclusion

The GCMS TQ8050 NX system delivers exceptional linearity, sensitivity and reproducibility for simultaneous quantitation of five nitrosamines in drug substances. Minimal matrix effects and high accuracy make this method a reliable tool for regulatory compliance and routine quality control.

References

• International Council for Harmonisation. M7 R1 Assessment and Control of DNA Reactive Mutagenic Impurities in Pharmaceuticals to Limit Potential Carcinogenic Risk