Analysis of N-nitroso-fenfluramine using LC-MS

Significance of N-nitroso-Fenfluramine Analysis

Nitrosamines are recognized carcinogens that can form in drug substances and dietary supplements. Monitoring N-nitroso-fenfluramine is crucial to ensure consumer safety and regulatory compliance in pharmaceutical and food matrices.

Objectives and Study Overview

This study presents a provisional LC-MS method for simultaneously detecting and quantifying fenfluramine and its N-nitroso derivative in diet food capsules. The approach employs methanolic extraction followed by chromatographic separation and mass spectrometric analysis.

Methodology

Sample preparation involved extracting 50 mg of capsule content with 5 mL methanol. Chromatographic separation was carried out on a C18 column using a gradient from 30% to 80% acetonitrile with 0.1% trifluoroacetic acid. Detection modes included full scan (m/z 100–400) and selected ion monitoring (SIM).

Used Instrumentation

• LCMS-2010A system with electrospray ionization (ESI) in positive mode
• Phenomenex LUNA 5 µ C18(2) column (2.0 mm × 150 mm)
• 0.1% trifluoroacetic acid in water (mobile phase A) and in acetonitrile (mobile phase B)

Main Results and Discussion

Fenfluramine eluted at approximately 6.0 minutes with an [M+H]+ ion at m/z 232.0. N-nitroso-fenfluramine appeared between 16.5 and 17.5 minutes, showing two isomeric peaks at m/z 261.0 and an acetonitrile adduct at m/z 302.0. SIM analysis achieved a detection limit of 1 ng/mL (approximately 2 pg on-column), with linearity from 1 to 100 ng/mL (R² > 0.999).

Benefits and Practical Applications

• Efficient screening of nitrosamine impurities in dietary supplements and pharmaceuticals
• High sensitivity enables stringent quality control and regulatory adherence
• Minimal sample preparation and rapid analysis support routine laboratory workflows

Future Trends and Opportunities

Advancements may include high-resolution mass spectrometry for enhanced selectivity, automated sample handling, expanded nitrosamine panels, and integration of data analytics for improved decision-making in safety assessments.

Conclusion

The provisional LC-MS method on the LCMS-2010A platform provides a robust, sensitive, and reproducible approach for detecting fenfluramine and its N-nitroso derivative, contributing to effective safety monitoring and regulatory compliance in pharmaceutical and food industries.