Herbal Drugs: USP introduces Acceptance Criteria for PAHs

Following the draft version published last year, the USP now introduced testing on Polycyclic aromatic hydrocarbons (PAHs) in the gereral chapter  <561> Articles of Botanical Origin (ABOs). The chapter will become official on 1 December 2026.

Analytical Procedure and Acceptance Criteria

Polycyclic aromatic hydrocarbons (PAHs) are carbon- and hydrogen-based compounds with two or more fused aromatic rings. Some PAHs, including benzo[a]pyrene, are genotoxic and carcinogenic. Medicinal plants may become contaminated through environmental exposure or post-harvest processing, particularly drying. 

The analytical procedure for PAH detection is based on Gas Chromatography (GC) coupled with Mass spectrometry (quadrupole time-of-flight, Q-TOF) (GC-MS) using Electron impact (EI+) as onization mode. The acceptance criteria are the following:

• Benzo[a]pyrene: max. 10.0 ppb
• Sum of benzo[a]pyrene, chrysene, benz[a]anthracene, and benzo[b]fluoranthene: max. 50.0 ppb

More information is available in the USP chapter <561> Articles of Botanical Origin.