Isotope dilution-GC-MS/MS analysis of 16 polycyclic aromatic hydrocarbons in selected medicinal herbs used as health food additives

Abstract

Medicinal herbs have a very important role in health protection and disease control, and have been used in health foods. Polycyclic aromatic hydrocarbons (PAHs) have carcinogenic, biological and mutagenic effects. In this paper, the content of 16 PAHs as representative contaminants in nine Chinese medicinal herbs, as additives for health foods, was investigated in order to ensure food safety from this source. A highly sensitive isotope dilution-gas chromatography-tandem mass spectrometry (ID-GC-MS/MS) method combined with gel permeation chromatography (GPC) and solid-phase extraction (SPE) was developed. Calibration curves showed good linearity for all PAHs (R 2 > 0.999), and the limit of quantification (LOQ) ranged from 0.42 to 2.7 µg kg−1. Average recoveries for these compounds were in the range of 52.5–117%, 52.6–119% and 81.4–108% at the concentrations of 10, 50 and 250 µg kg−1 with RSD of 1.8–15%, 0.9–15% and 1.0–15%, respectively. The proposed method was used for the analysis of nine Chinese medicinal herbs. Total levels of PAHs varied from 98.2 µg kg−1 (cassia seed) to 2245 µg kg−1 (eucommia bark). The highest level was found for phenanthrene (Phe) in liquorice root (631.3 µg kg−1), indigowoad leaf (551.0 µg kg−1), rose flower (435.2 µg kg−1) and eucommia bark (432.3 µg kg−1). The proposed method could provide a useful basis for safety monitoring of herbs and risk management for PAHs in the health food industry.