GC–MS to Determine Polycyclic Aromatic Hydrocarbons in Acai Foods

A recent study from scientists at the University of Campinas in Campinas, Brazil and Iowa State University in Ames, Iowa, combined vacuum-assisted sorbent extraction (VASE) and gas chromatography-mass spectrometry (GC–MS) to determine polycyclic aromatic hydrocarbons in açaí-based food products. Their findings were published in the Journal of Chromatography A (1).

The amazon acai fruit (Euterpe oleracea) | Image Credit: © Alexander Ruiz - stock.adobe.com

Chemical contaminants have become noteworthy to the scientific community because of their harmful effects on human health. Polycyclic aromatic hydrocarbons (PAHs) stand out as an important group of carcinogenic molecules and are most frequently detected in foods within the chemical contaminants group. Consisting of hydrogen and carbon atoms arranged in two or more fused aromatic (benzene) rings, PAHs may form in foods by thermal processing or be derived from environmental sources, such as contaminated water or soil. In the environment, PAHs can be formed through incomplete combustion of organic carbonaceous materials or through emission processes from natural or anthropogenic sources. This can prove dangerous, as exposure to some PAHs can cause nausea, diarrhea, cataracts, and even cancer, among other diseases (2).

In this study, vacuum-assisted sorbent extraction (VASE) and gas chromatography-mass spectrometry (GC–MS) were combined and utilized for the simultaneous analysis of fifteen PAHs, including light and heavy PAHs, in açaí-based food products (AFPs). Açaí are inch-long, reddish-purple berries that comes from a South American palm tree. These berries contain antioxidants, or nutrients that protect against cell damage caused by free radicals (3). VASE, which was first introduced in 2016 and has become a new trend for vacuum extraction of semi-volatile and volatile organic compounds (VOCs), offers practical conditions of analysis due to its easy-to-operate system that does not require high technical skills to operate. Additionally, according to the scientists, VASE provides satisfactory precision results once analytes are extracted in their entirety when the system is operated near equilibrium conditions. Moreover, VASE is particularly selective for compounds amenable to gas chromatography-mass spectrometry (GC–MS) analysis, such as PAH quantification in food matrices.

This method, which requires no organic solvents, is also amenable to full automation. To achieve optimal analytical extraction conditions, VASE parameters including stirring rate, extraction time, desorption temperature, desorption time, preheat time, and preheat temperature were optimized using sequential multivariate optimization. From there, the approach was deemed eco-friendly and used for the simultaneous determination of 15PAHs via GC–MS. No organic solvent was used to perform the extraction of analytes for chromatographic analysis. Additionally, no clean-up step was required to obtain an interferent-free chromatogram.

The method was validated and yielded limits of quantification below 1 µg kg⁻¹ for all analytes, with recoveries ranging from 65% to 112% and good precision (≤ 11% relative standard deviation). Additionally, the greenness and practical aspects of the method were investigated using the Green Analytical Procedure Index (GAPI), eco-scale, and the Blue Applicability Grade Index (BAGI), respectively. The method fulfilled the requirements for consideration as a green and practical method, which are ideal conditions for routine analysis. The optimization resulted in a method that meets the requirements outlined in the validation guidelines, reaching LOQ values ranging from 0.01 to 0.8 µg kg^−1. No PAHs were detected in any samples investigated. With these findings, the VASE-GC–MS method was viewed as an attractive procedure for determining and quantifying PAHs in other types of food samples. Further, the achieved analytical parameters make this method suitable for PAH analyses.

References

(1) Nascimento, L. E. S.; Thapa, B.; Oliveira, W. d. S.; et al. A Practical and Eco-Friendly Method for the Determination of Polycyclic Aromatic Hydrocarbons in Açaí-Based Food Products by Vacuum-Assisted Sorbent Extraction Coupled to Gas Chromatography-Mass Spectrometry. J. Chromatogr. A 2024, 1730, 465104. DOI: 10.1016/j.chroma.2024.465104

(2) Polycyclic Aromatic Hydrocarbons (PAHs). Illinois Department of Public Health 2024. http://www.idph.state.il.us/cancer/factsheets/polycyclicaromatichydrocarbons.htm (accessed 2024-8-1)

(3) Bruce, D. F.; Begum, J. Acai Berries and Acai Berry Juice – What Are the Health Benefits? WebMD 2023. https://www.webmd.com/diet/acai-berries-and-acai-berry-juice-what-are-the-health-benefits (accessed 2024-8-1)