Rapid Detection and Identification of Synthetic Phosphodiest erase Type-5 Inhibitors in Counterfeit and Adulterated Products using the Atmospheric Solids Analysis Probe

Significance of the Topic

Ambient desorption ionization methods like ASAP enable rapid, minimal-prep detection of synthetic PDE-5 inhibitors in counterfeit and adulterated products, addressing public health threats and high-throughput analytical needs.

Objectives and Overview of the Study

This study applied the Waters Atmospheric Solids Analysis Probe (ASAP) coupled with high-resolution mass spectrometry to rapidly detect and identify synthetic phosphodiesterase type-5 inhibitors in counterfeit erectile dysfunction tablets and adulterated herbal supplements.

Methodology and Instrumentation

• Sample selection: Counterfeit brand and generic ED tablets and five herbal dietary supplements purchased online.
• ASAP-MS analysis: Samples applied to glass capillaries and introduced into a heated gas stream (100–450 °C) for vaporization; corona discharge ionization in APCI mode.
• Instrument: Waters LCT Premier XE high-resolution TOF-MS operating in combined ESCi (ESI + APCI) mode; key parameters: corona current 5 µA, desolvation gas 500 L/hr, acquisition range 100–1000 amu.

Main Results and Discussion

• Counterfeit tablets: ASAP-MS identified correct API in genuine tablets (sildenafil, vardenafil, tadalafil) and detected wrong or absent APIs in imitations within 20 minutes without chromatography.
• Herbal supplements: All five HDS samples contained undeclared sildenafil, tadalafil, or analogues such as thiohomosildenafil, confirmed by accurate mass and elemental composition.
• Comparison with UPLC-MS/MS: ASAP findings were consistent with detailed chromatographic analyses, validating the rapid screening approach.

Benefits and Practical Applications

• Minimal or no sample preparation reduces analysis time and bottlenecks associated with LC/GC separations.
• Rapid yes/no screening capability guides decisions on further chromatographic characterization.
• High-resolution mass measurement and elemental composition facilitate confident compound identification in counterfeit and adulterated products.
• Enhanced laboratory throughput supports regulatory and pharmaceutical quality control efforts.

Future Trends and Opportunities

• Integration with automated sampling systems for large-scale screening of pharmaceuticals and supplements.
• Expansion to other classes of illicit or adulterant compounds across food, cosmetics, and forensic matrices.
• Coupling with ion mobility or advanced fragmentation techniques to resolve isomers and novel analogues.
• Development of portable ASAP-MS platforms for in-field screening by customs and regulatory agencies.

Conclusion

ASAP coupled with high-resolution MS offers a robust, high-throughput screening tool for the rapid detection of synthetic PDE-5 inhibitors in counterfeit and adulterated products, significantly reducing time and resources compared to traditional chromatography-based methods.

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