Polycyclic Aromatic Hydrocarbons In Olive Oil Research Articles

A Review on the Occurrence and Analytical Determination of PAHs in Olive Oils.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental and processing contaminants, which may contaminate vegetable oils due to atmospheric fall-out or bad production practices. Due to their carcinogenic and toxic effects, surveillance schemes and mitigation strategies are needed to monitor human exposure to PAHs. In particular, due to the lipophilic nature of these substances, edible oils may present unsafe levels of these compounds. Among these, olive oil, and in particular extra virgin olive oil, is a high-value commodity, also known for its health benefits. Therefore, the occurrence of contaminants in this product is not only of health concern but also causes economic and image damage. In this review, an overview of the occurrence of PAHs in all categories of olive oil is provided, as well as a description of the official methods available and the analytical developments in the last 10 years.

GC-MS analysis of polycyclic aromatic hydrocarbons in bottled olive oil marketed in Lebanon.

Lebanon has witnessed elevated levels of pollution over the last few years due to increased waste incineration, emissions from vehicles and electricity generators, and mass demonstrations involving the burning of tires. The resultant generation of polycyclic aromatic hydrocarbons (PAHs) from the incomplete combustion of organic materials present in these sources may contaminate various foods including olive oil. Lebanon has a sizeable olive oil industry that is a main pillar of its agricultural sector. In this study, we investigated the occurrence of 16 semi-volatile lipophilic organic pollutants in 25 bottled olive oil brands, marketed in Lebanon, using a solid phase extraction (SPE) method followed by gas chromatography mass spectrometry (GC-MS). PAHs were detected in 60% of brands (41% of samples) where 12% of brands contained traces of probably carcinogenic (Class 2A) compounds and 56% of brands contained traces of possibly carcinogenic (Class 2B) compounds. One brand revealed levels of benzo[a]pyrene of 9.45μg/kg and 11.9μg/kg in batches collected over two production dates which are higher than the limit set by the European Commission for benzo[a]pyrene in food (2μg/kg). The same batches contained a total of 19.3μg/kg and 26.7μg/kg of the four PAHs: benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, and chrysene which also exceeded the limit set by the EC for the combination of these four PAHs in olive oil (10μg/kg). This study is the first-of-its-kind in Lebanon and emphasizes the need to perform adequate cleanup steps in the manufacturing process in order to reduce the content of carcinogenic PAHs in olive oil.

Determination of four polycyclic aromatic hydrocarbons in olive oil by high performance liquid chromatography-fluorescent detection

A method for the determination of four polycyclic aromatic hydrocarbons (PAHs) such as benzo[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene in olive oil by high performance liquid chromatography-fluorescent detection (HPLC-FLD) was developed. The olive oil samples were diluted with isopropanol and cleaned-up by a solid phase extraction cartridge with π-π specificity. Critical isomers were separated by gradient elution with water-acetonitrile on an Agilent ZORBAX Eclipse PAH column (100 mm×2.1 mm, 1.8 μ m). The calibration was performed by the use of matrix-matched calibration standards. The results showed that there were good linear relationships for the four PAHs in the range of 2.4-40 μ g/L with correlation coefficients of 0.9990-0.9999. The limits of quantification (LOQs) ranged from 0.147 to 0.413 μ g/L, and the recoveries of the spiked samples ranged from 95.5% to 103.2%. The intra-day and inter-day precisions were in the ranges of 0.10%-1.69% and 2.48%-2.93% (n=5), respectively. The method has the characteristics of high sensitivity, low detection limit and good precision, and is suitable for rapid and accurate quantitative detection of the four PAHs in olive oil.

Development and optimisation of a dopant assisted liquid chromatographic-atmospheric pressure photo ionisation-tandem mass spectrometric method for the determination of 15 + 1 EU priority PAHs in edible oils

European food legislation defines a set of 16 polycyclic aromatic hydrocarbons (PAHs) as of high concern for human health. The EU set contains structurally very similar PAHs with ring numbers between 4 and 6, and so raises some separation aspects and problems, which were not experienced with traditionally analysed PAHs. Many of the currently applied gas chromatographic mass spectrometric (GC–MS) methods suffer from separation problems, while high performance liquid chromatography with fluorescence detection (HPLC-FLD) is neither capable of detecting the whole set of EU priority PAHs nor does it (compared to GC–MS) allow structural identification. In addition HPLC-FLD shows limitations with difficult matrices due to interferences. The aim of this paper is to fill this gap by describing a liquid chromatographic dopant assisted atmospheric pressure photo ionisation tandem mass spectrometric (LC-DA-APPI-MS/MS) method for the determination of 15+1 EU priority PAHs in edible oil, which complies with the requirements set by European food legislation. Measurements were performed in positive ion mode. Anisole at a flow rate of 30μl/min was used as dopant. Sample preparation was performed offline by donor–acceptor complex chromatography (DACC). Compared to HPLC-FLD methods the presented method enables the determination of all 15+1 EU priority PAHs at the low μg/kg concentration range including less fluorescence active compounds like benzo[j]fluoranthene and indeno[1,2,3-cd]pyrene. By analysing four reference materials it could be demonstrated that this method provides accurate results and is sufficiently sensitive for food control purposes. Statistically significant differences between the reference values and the measured analyte contents were not found. The method performs well also for very complex samples. Repeatability relative standard deviations (RSDr) of the determination of the target PAHs in olive oil were for most analytes below 5%. The limit of detection (LOD) of the method met the requirement set by EU legislation (0.3μg/kg).

Polycyclic Aromatic Hydrocarbons in Spanish Olive Oils: Relationship between Benzo(a)pyrene and Total Polycyclic Aromatic Hydrocarbon Content

Samples of Spanish virgin olive oils (VOOs) from different categories, origins, varieties, and commercial brands were analyzed by HPLC with a programmable fluorescence detector to determine the content of nine heavy polycyclic aromatic hydrocarbons (PAHs): benzo(a)anthracene, chrysene, benzo(e)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perilene, and indeno(1,2,3-c,d)pyrene. Samples of olive pomace and crude olive pomace oils were also investigated. Benzo(a)pyrene concentrations were below the allowed limit in the European Union (2 microg/kg) in 97% of the VOO samples. Only those samples coming from contaminated olive fruits or obtained in oil mills with highly polluted environments exceeded this value. High correlation coefficients (<0.99) were obtained between the contents of benzo(a)pyrene and the sum of the nine PAHs for all of the analyzed categories, suggesting that benzo(a)pyrene could be used as a marker of the content of these nine PAHs in olive oils.

Determination of polycyclic aromatic hydrocarbons in olive oil by a completely automated headspace technique coupled to gas chromatography‐mass spectrometry

A new and completely automated method for the determination of ten relevant polycyclic aromatic hydrocarbons (PAHs) in olive oil is proposed using an extraction by the headspace (HS) technique. Quantification and confirmation steps are carried out by gas chromatography-mass spectrometry (GC-MS) combining simultaneously selected-ion monitoring (SIM) and tandem mass spectrometry (MS/MS). This combination offers on one hand an increased sensitivity and on the other hand, selective and reliable qualitative information. Sample pretreatment or clean-up are not necessary because the olive oil sample is put directly into an HS vial, automatically processed by HS and introduced into the GC-MS instrument for analysis. Because of its high selectivity and sensitivity, a triple-quadrupole (QqQ) detector coupled with the gas chromatograph allows us to limit handling. Each sample is completely processed in approximately 63 min (45 min for HS isolation and 18 min for GC-MS determination), a reduced time compared with previously published methods. The chemical and instrumental variables were preliminarily optimized using uncontaminated olive oil samples spiked with 25 microg kg(-1) of each target compound. The final method was validated to ensure the quality of the results. The precision was satisfactory, with relative standard deviation (RSD) values in the range 3-9%. Recovery rates ranged from 96 to 99%. Limits of detection (LOD) were calculated as 0.02-0.06 microg kg(-1) and the limits of quantification (LOQ) were obtained as 0.07-0.26 microg kg(-1). It must be mentioned that the LOD and LOQ are much lower than the maximum levels established by the European Union (EU) in oils and fats intended for direct human consumption or for use as an ingredient in foods, which are set at 2 microg kg(-1). All the figures of merit are completely in accordance with the latest EU legislation. This fact makes it possible to consider the proposed method as a useful tool for the control of PAHs in olive oils.

Sample Preparation Improvement in Polycyclic Aromatic Hydrocarbons Determination in Olive Oils by Gel Permeation Chromatography and Liquid Chromatography with Fluorescence Detection

The determination of 15 polycyclic aromatic hydrocarbons (PAHs) in olive oil samples has been improved in order to obtain a fast methodology with a low limit of detection through the combination of liquid-liquid extraction with acetonitrile and preparative gel permeation chromatography (GPC) prior to the injection of purified extracts into a C18 column. Acetonitrile-water was used as the mobile phase with a gradient from 50 to 95%, w/w, acetonitrile in 30 min. The oven temperature was maintained at 15 degrees C, and fluorometric detection was made at a fixed excitation wavelength of 264 nm and variable, optimal emission wavelength for each analyte ranging from 352 nm for 11-H-benzo(b)fluorene to 500 nm for indeno(1,2,3-cd)pyrene. Recovery for all the compounds studied varied from 75 to 111%, and limit of detection values from 0.05 ng/g for benzo(k)fluoranthene to 0.48 ng/g for indeno(1,2,3-cd)pyrene, corresponding to 0.09 ng/g benzo(a)pyrene. Results were compared with those obtained by liquid-liquid extraction followed by a cleanup on silica and a direct GPC treatment of oil samples diluted in dichloromethane, 2 other methodologies that are appropriate for quantifying PAHs in olive oils. However, the proposed method improves the determination limits, reduces the time of analysis, and provides a highly stable baseline for sample chromatograms.