Determination of Persistent Organic Pollutants (POPs) in Propolis by Solid-Phase Extraction (SPE) and Gas Chromatography – Mass Spectrometry (GC-MS)

Abstract

Bee products produced in environments with persistent organic pollutants (POPs) may be contaminated by these compounds. Propolis usually consists of beeswax, resins, water, inorganic and phenolic substances, and essential oils. Although there are some studies on the detection of POPs in honey and some bee products, these are quite limited. Because propolis is a botanical-based and highly complex matrix, and thus difficult to analyze, a reliable and selective method based on solid-phase extraction (SPE) combined with gas chromatography-mass spectrometry was developed for the determination of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the propolis. All analytes were extracted with acetonitrile and centrifuged for 10 min at 4000 rpm and 6 °C in a refrigerated centrifuge. The samples were filtered using a homemade SPE cartridge containing C18, primary-secondary amine, and magnesium sulfate. The residue collected with acetonitrile was subsequently analyzed by gas chromatography – mass spectrometry (GC-MS). The proposed method was validated according to the Eurachem guidelines and applied directly to the collected propolis samples. The results show that the method may be used successfully in residue monitoring laboratories for the determination of OCPs, PCBs and PBDEs in propolis.