Rapid detection of illegal adulterants in dietary supplements with Raman

Importance of the topic

Dietary supplements are often marketed without rigorous oversight and may contain undeclared pharmaceutical compounds that pose serious health risks. Rapid, onsite screening methods are essential to protect consumers and support regulatory enforcement.

Objectives and study overview

This application note presents a surface enhanced Raman spectroscopy based approach for the fast detection of illegal adulterants in dietary supplements. The study covers a proof of concept screening of known adulterants and a real world example analyzing honey products marketed for male vitality.

Methodology and instrumentation

Sample preparation involved simple extraction of the target analytes into organic solvents followed by application to paper based SERS substrates. Raman spectra were acquired using a portable Raman analyzer and processed with library matching software.

Main results and discussion

Initial screening of 23 pharmaceutical adulterants identified 11 compounds that produced strong SERS signals on silver paper substrates. Limits of identification ranged from 0.1 to 5 percent by weight. Common excipients such as microcrystalline cellulose and magnesium stearate showed negligible interference. Analysis of commercial honey samples confirmed undeclared sildenafil and tadalafil at levels consistent with laboratory GC MS results. Both silver and gold nanoparticle substrates were evaluated to optimize signal strength for different analytes.

Benefits and practical applications of the method

• High sensitivity and selectivity for trace adulterants
• Minimal interference from filler materials
• Rapid results within seconds per measurement
• Portable and cost effective for field deployment

Future trends and potential applications

Further development of nanoparticle substrates and expansion of spectral libraries will enhance detection capabilities. Integration with automated data analysis and mobile platforms will broaden the use of SERS for quality control across food and pharmaceutical industries.

Conclusion

Surface enhanced Raman spectroscopy combined with portable analyzers provides a fast, sensitive, and user friendly approach to detect illegal adulterants in dietary supplements. This method can improve consumer safety and streamline regulatory screening.

References

1. Rizzo S Weesepoel Y Erasmus S Sinkeldam J Piccinelli AL Ruth van Qualitative screening for illicit adulterants in dietary supplements Heliyon 2023 9 e18509
2. U.S Food and Drug Administration Tainted honey based products with hidden active drug ingredients 2025