Liquid–liquid extraction of polycyclic aromatic hydrocarbons in four different edible oils from China

Deep eutectic solvent for the extraction of polycyclic aromatic compounds in fuel, food and environmental samples

Polycyclic aromatic compounds (PACs) encompass a wide variety of organic analytes that have mutagenic and carcinogenic potentials for human health and are recalcitrant in the environment. Evaluating PACs levels in fuel (e.g., gasoline and diesel), food (e.g., grilled meat, fish, powdered milk, fruits, honey, and coffee) and environmental (e.g., industrial effluents, water, wastewater and marine organisms) samples are critical to determine the risk that these chemicals pose. Deep eutectic solvents (DES) have garnered significant attention in recent years as a green alternative to traditional organic solvents employed in sample preparation. DES are biodegradable, have low toxicities, ease of synthesis, low cost, and a remarkable ability to extract PACs. However, no comprehensive assessment of the use of DESs for extracting PACs from fuel, food and environmental samples has been performed. This review focused on research involving the utilization of DESs to extract PACs in matrices such as PAHs in environmental samples, NSO-HET in fuels, and bisphenols in foods. Chromatographic methods, such as gas chromatography (GC) and high-performance liquid chromatography (HPLC), were also revised, considering the sensibility to quantify these compound types. In addition, the characteristics of DES and advantages and limitations for PACs in the context of green analytical chemistry principles (GAC) and green profile based on metrics provide perspective and directions for future development.

Analysis of organochlorines and polycyclic aromatic hydrocarbons designed for pollutant biomonitoring in three seabird matrices

Pollutant biomonitoring demands analytical methods to cover a wide range of target compounds, work with minimal sample amounts, and apply least invasive and reproducible sampling procedures. We developed a method to analyse 68 bioaccumulative organic pollutants in three seabird matrices: plasma, liver, and stomach oil, representing different exposure phases. Extraction efficiency was assessed based on recoveries of spiked surrogate samples, then the method was applied to environmental samples collected from Scopoli's shearwater (Calonectris diomedea). Extraction was performed in an ultrasonic bath, purification with Florisil cartridges (5 g, 20 mL), and analysis by GC-Orbitrap-MS. Quality controls at 5 ng yielded satisfactory recoveries (80-120%) although signal intensification was found for some compounds. The method permitted the detection of 28 targeted pollutants in the environmental samples. The mean sum of organic pollutants was 4.25 ± 4.83 ng/g in plasma, 1634 ± 2990 ng/g in liver, and 233 ± 111 ng/g in stomach oil (all wet weight). Pollutant profiles varied among the matrices, although 4,4'-DDE was the dominant compound overall. This method is useful for pollutant biomonitoring in seabirds and discusses the interest of analysing different matrices.

Recent Advances in Sample Preparation and Chromatographic/Mass Spectrometric Techniques for Detecting Polycyclic Aromatic Hydrocarbons in Edible Oils: 2010 to Present

Polycyclic aromatic hydrocarbons are considered to be potentially genotoxic and carcinogenic to humans. For non-smoking populations, food is the main source of polycyclic aromatic hydrocarbons exposure. Due to their lipophilic nature, oils and fats rank among the food items with the highest polycyclic aromatic hydrocarbon content. Consequently, the detection of polycyclic aromatic hydrocarbons in edible oils is critical for the promotion of human health. This paper reviews sample pretreatment methods, such as liquid-phase-based extraction methods, adsorbent-based extraction methods, and the QuEChERS (quick, easy, cheap, effective, rugged, and safe) method, combined with detection techniques like mass spectrometry and chromatography-based techniques for accurate quantification of polycyclic aromatic hydrocarbons in edible oils since 2010. An overview on the advances of the methods discussed herein, along with a commentary addition of current challenges and prospects, will guide researchers to focus on developing more effective detection methods and control measures to reduce the potential risks and hazards posed by polycyclic aromatic hydrocarbons.

Supramolecular chemistry of liquid-liquid extraction

Liquid-Liquid Extraction (LLE) is a venerable and widely used method for the separation of a targeted solute between two immiscible liquids. In recent years, this method has gained popularity in the supramolecular chemistry community due to the development of various types of synthetic receptors that effectively and selectively bind specific guests in an aqueous medium through different supramolecular interactions. This has eventually led to the development of state-of-the-art extraction technologies for the removal and purification of anions, cations, ion pairs, and small molecules from one liquid phase to another liquid phase, which is an industrially viable method. The focus of this perspective is to furnish a vivid picture of the current understanding of supramolecular interaction-based LLE chemistry. This will not only help to improve separation technology in the chemical, mining, nuclear waste treatment, and medicinal chemistry sectors but is also useful to address the purity issue of the extractable species, which is otherwise difficult. Thus, up-to-date knowledge on this subject will eventually provide opportunities to develop large-scale waste remediation processes and metallurgy applications that can address important real-life problems.

Formation, migration, derivation, and generation mechanism of polycyclic aromatic hydrocarbons during frying

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic and lipophilic, which can be found in frying system. This review summarized the formation, migration and derivation for PAHs, hypothesized the possible mechanism for PAHs generation during frying and presented the research prospects. Some factors like high oil consumption, high temperature, long time and oil rich in unsaturated fatty acids promoted the formation of PAHs and the presence of antioxidants inhibited the PAHs formation. The effect of proteins and carbohydrates in foods on the formation of PAHs is inconclusive. The formed PAHs were migrated into food and air. Moreover, some PAHs transformed into more toxic PAHs-derivatives during frying. The generation of PAHs may be related to low-barrier free radical-mediated reaction and the unsaturated hydrocarbons may be precursors of PAHs during frying. In future, the isotope tracer technology and on-line detection may be applied to discover intermediates and provide clues for studying PAHs generation mechanisms.

Characterization of Polycyclic Aromatic Hydrocarbons (PAHs) associated with fine aerosols in ambient atmosphere of high-altitude urban environment in Sikkim Himalaya

Polycyclic Aromatic Hydrocarbons (PAHs) compounds are ubiquitous in ambient air due to their persistence, carcinogenicity, and mutagenicity. Gangtok being one of the cleanest cities in India located in Eastern Himalayan region, witnesses high developmental activities with enhanced urbanization affecting the ambient air quality. The present study aims to measure PM_2.5 and PAHs in the ambient atmosphere of the Sikkim Himalaya to understand the influence of natural and anthropogenic activities on aerosol loading and their chemical characteristics. The PM_2.5 samples were collected and analysed for the duration from Jan 2020 to Feb 2021.The seasonal mean concentrations of PM_2.5 and PAHs were observed to be high during autumn and low during summer season. Overall, the annual mean concentration of PM_2.5 was found higher than the prescribed limit of World Health Organization and National Ambient Air Quality Standards. The concentration of the 16 individual PAHs were found to be highest during autumn season (55.26 ± 37.15 ng/m³). Among the different PAHs, the annual mean concentration of fluorene (3.29 ± 4.07 ng/m³) and naphthalene (1.15 ± 3.76 ng/m³) were found to be the highest and lowest, respectively. The Molecular Diagnostic Ratio (MDR) test reveals higher contribution from heavy traffic activities throughout the winter and autumn seasons. The other possible sources identified over the region are fossil fuel combustion, and biomass burning. The multivariate statistical analysis (Multifactor Principal Component Analysis) also indicates a strong association between PM_2.5 /PAHs and meteorological variables across the region in different seasons. The precipitation and wind pattern during the study period suggests that major contribution of the PM_2.5 and PAHs were from local sources, with minimal contribution from long-range transport. The findings are important for comprehending the trends of PAH accumulation over a high-altitude urban area, and for developing sustainable air quality control methods in the Himalayan region.

One-step electrodeposition of poly(o-phenylenediamine)-Zn composite on plaswood propeller as an extraction device for polycyclic aromatic hydrocarbons in coffee

Coffee beans can be contaminated during roasting by polycyclic aromatic hydrocarbons (PAHs), some of which have been classified as carcinogens. An extraction device for PAHs in coffee drinks was designed with six compact DC motors rotating six sorbents. The sorbents were plaswood propellers modified by one-step electrodeposition of a poly(ortho-phenylenediamine) and Zn composite (PoPD-Zn). Benzo(a)anthracene (BaA), chrysene (Chry), benzo(b)fluoranthene (BbF), and benzo(a)pyrene (BaP) were chosen as representative PAHs. Scanning electron micrographs of the PoPD-Zn showed a porous structure. The extracted PAHs were quantified by gas chromatography coupled with a flame ionization detector. Detected concentrations of PAHs in coffee drink samples were as follows: BaA 1.4 ± 0.4 to 16.5 ± 0.8 µg L^-1; Chry 0.5 ± 0.2 to 2.1 ± 0.5 µg L^-1; BbF 2.2 ± 0.6 µg L^-1; and BaP 6.2 ± 1.0 µg L^-1. Good recoveries ranging from 82.7 ± 1.9% to 99.0 ± 0.5% were obtained.

Benzo[a]pyrene toxicokinetics in humans following dietary supplementation with 3,3'-diindolylmethane (DIM) or Brussels sprouts

Utilizing the atto-zeptomole sensitivity of UPLC-accelerator mass spectrometry (UPLC-AMS), we previously demonstrated significant first-pass metabolism following escalating (25-250 ng) oral micro-dosing in humans of [14C]-benzo[a]pyrene ([14C]-BaP). The present study examines the potential for supplementation with Brussels sprouts (BS) or 3,3'-diindolylmethane (DIM) to alter plasma levels of [14C]-BaP and metabolites over a 48-h period following micro-dosing with 50 ng (5.4 nCi) [14C]-BaP. Volunteers were dosed with [14C]-BaP following fourteen days on a cruciferous vegetable restricted diet, or the same diet supplemented for seven days with 50 g of BS or 300 mg of BR-DIM® prior to dosing. BS or DIM reduced total [14C] recovered from plasma by 56-67% relative to non-intervention. Dietary supplementation with DIM markedly increased Tmax and reduced Cmax for [14C]-BaP indicative of slower absorption. Both dietary treatments significantly reduced Cmax values of four downstream BaP metabolites, consistent with delaying BaP absorption. Dietary treatments also appeared to reduce the T1/2 and the plasma AUC(0,∞) for Unknown Metabolite C, indicating some effect in accelerating clearance of this metabolite. Toxicokinetic constants for other metabolites followed the pattern for [14C]-BaP (metabolite profiles remained relatively consistent) and non-compartmental analysis did not indicate other significant alterations. Significant amounts of metabolites in plasma were at the bay region of [14C]-BaP irrespective of treatment. Although the number of subjects and large interindividual variation are limitations of this study, it represents the first human trial showing dietary intervention altering toxicokinetics of a defined dose of a known human carcinogen.

Polybutylene succinate/modified cellulose bionanocomposites as sorbent for needle trap microextraction

In this work, different polybutylene succinate/modified cellulose bio-nanocomposites were synthesized by solving the casting method and then used as a new sorbent for needle trap microextraction of some polycyclic aromatic hydrocarbons from the water samples in headspace mode. The surface of cellulose nanocrystalline was modified using aminosilane groups to improve the dispersion of nanoparticles in the polybutylene succinate matrix. The characterization of synthesized nanocomposites, were performed using TGA, SEM, BET analysis and FT-IR spectroscopy. Adding modified nanocrystalline cellulose to a polybutylene succinate matrix increased the surface area, and thermal and mechanical stabilities. The significant parameters of the sorbent extraction process, including the amount of modified cellulose nanoparticles, the extraction time, and temperatures and salt content, were studied and optimized. Under the optimized extraction conditions (extraction time of 25 min, and extraction temperature of 50 °C), an analytical method for selected polycyclic aromatic hydrocarbons with low detection limits (0.75-1 ng L^-1) and the quantification limit (3-5 ng L^-1), good repeatability (3-7% at 20 ng L^-1), and reproducibility (9%-14%, n = 3) was developed. The linearity of the method was obtained in the range of 5-1000 ng L^-1 with R² > 0.9996. The enrichment factor was obtained for the spiked real aqueous samples (at 50 ng L^-1) in the range of 276-311. Also, the performance of the developed method was studied via the extraction of selected analytes in real water samples, and the relative recovery values were found to be in the range of 98-103%.

Application of sulfur-coated magnetic carbon nanotubes for extraction of some polycyclic aromatic hydrocarbons from water resources

In the present work, novel sulfur-coated magnetic carbon nanotubes (MCNTs-S) material was fabricated by S coating on the MCNTs using a simple heating procedure. TGA, EDX, XRD, TEM, and VSM were employed to characterize the as-prepared composite. Using HPLC-UV system, the produced superparamagnetic sorbent was employed for the extraction and measurement of trace levels of five polycyclic aromatic hydrocarbons (PAHs) in environmental waters. The synergistic effect of the sulfur layer and CNTs substrate is primarily responsible for the remarkable extraction efficiency of the MCNTs-S sorbent towards PAHs. The experimental factors including MCNTs-S dosage, sorption time, elution solvent, ionic strength and solution pH were explored and optimized. Considering that the ionic strength and pH do not have any impact on the PAHs extraction, as a result, there is no need the unnecessary adjustment of the water samples. The linear dynamic ranges and detection limits under optimal conditions were in the range of 0.05-0.11 ng mL^-1 and 0.2-150 ng mL^-1, respectively. The analysis of PAHs in the real samples (sea water and river water) using this approach was successfully assessed with appropriate recovery values (94.6%-99.0%).

Rapid Screening of 22 Polycyclic Aromatic Hydrocarbons Residues in Vegetable Oils by Gas Chromatography-Electrostatic Field Orbitrap High Resolution Mass Spectrometry

A method for simultaneous determination of 22 polycyclic aromatic hydrocarbons (PAHs) residues in vegetable oils by gas chromatography-electrostatic field orbitrap high resolution mass spectrometry (Orbitrap GC-MS) was established. The samples were vortexed with acetonitrile, centrifuged at 8,000 r/min for 5 min, and frozen at −70°C for 10 min. The extracts of upper layer were poured out, dried with nitrogen at 40°C, redissolved in dichloromethane, and measured by Orbitrap GC-MS. The matrix interference in vegetable oil could be effectively removed by determining the accurate mass number of target compounds under the full scan mode. Six typical vegetable oil samples (soybean oil, sesame oil, peanut oil, olive oil, rapeseed oil, sunflower oil) were used for method validation. The calibration curve displayed good linearity in the range of 1–100 ng/mL, with correlation coefficients > 0.9950. The limits of detection (LODs) were in the range of 0.10–0.60 μg/kg, and the limits of quantification (LOQs) were in the range of 0.35–2.00 μg/kg. The average spiked recoveries of 22 PAHs in 6 matrices at 5, 50 and 100 μg/kg levels were 76.4–115.4%, and the average relative standard deviations (RSDs) were 1.8–10.8%. The results showed that 22 PAHs were detected in 6 types of 90 edible vegetable oil samples in the Chinese market by this method. Meanwhile, the abundance of light PAHs (LPAHs) was higher than that of heavy PAHs (HPAHs), and its relative contribution of LPAHs to the total PAHs was higher. All levels of BaP conformed to the Chinese requirement of upper limit, 10 μg/kg. However, 13.3 and 11.1% of the samples exceeded the maximum limits of BaP and PAH4 set by EU, 2 and 10 μg/kg, respectively. The total concentrations of 22 PAHs (defined as PAH22) varies greatly among different oil species, and the average PAH22 contents were listed in descending order as follows: peanut oil > sesame oil > olive oil > rapeseed oil > soybean oil > sunflower seed oil. The established method effectively avoided interference from large amounts of lipids and pigments. Therefore, the method is simple, sensitive and suitable for rapid screening and confirmation of PAHs in vegetable oil.

Organochlorine pesticides and other pesticides in peanut oil: Residue level, source, household processing factor and risk assessment

Peanut oil, edible vegetable oil largely consumed in China, may be polluted with pesticides during both peanut cultivation and processing. In this study, we analyzed organochlorine pesticides, five currently used pesticides and two degradation products, in soils, seeds, peanuts, oil and dregs and systematically tracked variations of their levels in field soils and during the pressing process. The results showed that the application of metolachlor, pirimicarb and quizalofop-p-ethyl pesticides during peanut cultivation caused their concentrations in peanuts to increase. In most samples, the concentration of 3-phenoxybenzoic acid was higher than that of λ-cyhalothrin, and the variation trends of λ-cyhalothrin and 3-phenoxybenzoic acid in soil samples were similar, which indicate that after application, most λ-cyhalothrin may rapidly be degraded to 3-phenoxybenzoic acid. Regarding the pressing process of peanut oil, the sum of mass of oil and shells was less than the mass of the corresponding raw peanut. Compared with that in peanuts, the total mass of most pesticides in oil and shells was lower, while that of two degradation products was higher, an indication that the degradation products were still generated during the pressing process. Finally, the assessment of health risk of different age groups consuming the studied peanuts and peanut oil showed that the risk was very low.

A hierarchical porous composite magnetic sorbent of reduced graphene oxide embedded in polyvinyl alcohol cryogel for solvent assisted-solid phase extraction of polycyclic aromatic hydrocarbons

A hierarchical porous composite magnetic sorbent was fabricated and applied to the dispersive solvent assisted-solid phase extraction of five polycyclic aromatic hydrocarbons. A sorbent was first prepared by incorporating graphene oxide, calcium carbonate and magnetite nanoparticles into a polyvinyl alcohol cryogel. The graphene oxide was converted to reduced graphene oxide using ascorbic acid and a hierarchical porous structure was produced by reacting hydrochloric acid with incorporated calcium carbonate to generate carbon dioxide bubbles which created a second network. Before extracting the target analytes, extraction solvent was introduced into the hierarchical pore network of the sorbent. The extraction was based on the partition between the analytes and introduced extraction solvent and the adsorption of analytes on reduced graphene oxide. The extraction efficiency was enhanced through π-π and hydrophobic interactions between polycyclic aromatic hydrocarbons and reduced graphene oxide and extraction solvent. The extracted polycyclic aromatic hydrocarbons were determined using HPLC coupled with fluorescence detector. The developed method was applied to extract polycyclic aromatic hydrocarbons in disposable diaper, coffee and tea samples and recoveries from 84.5 to 99.4% were achieved with relative standard deviations below 7%. The developed sorbent exhibited good reproducibility and can be reused for ten cycles. This article is protected by copyright. All rights reserved.

Schemes for enhanced antioxidant stability in frying meat: a review of frying process using single oil and blended oils

Deep-fried meat products are widely popular. However, harmful compounds produced by various chemical reactions during frying have been shown to be detrimental to human health. It is of great necessity to raise practical suggestions for improving the oxidation problem of frying oils and frying conditions in some aspects. Vegetable oils are not as thermally stable as saturated fats, and blended oils have higher thermal stability than single oil. In this review, we discussed the oxidation problems frying oils and meats are subject to during frying, starting from the oil oxidation mechanism, the effects of different oils and fats on the quality of different fried meats under different conditions were concluded to alleviate the oxidation problem, to highlight the necessity of applying blended oils for frying, and effective antioxidants added to frying oils are also introduced, that would provide more convenient and practical options for obtaining higher quality of fried meat products and offer better understanding of the potential of blended frying oils for frying meat products.

A density-tunable liquid-phase microextraction system based on deep eutectic solvents for the determination of polycyclic aromatic hydrocarbons in tea, medicinal herbs and liquid foods

A novel density-tunable liquid-phase microextraction (DT-LPME) system was developed with high-density deep eutectic solvents (DESs) as extractant and low-density organic solvents as emulsifier and density regulator. DES-rich phase was induced to form in the bottom or in the top by adjusting the emulsifier amount. This system was used to directly extract polycyclic aromatic hydrocarbons (PAHs) from liquid and solid foods, and the obtained DES-rich phase was easy to be collected for quantification. The method (LPME with HPLC-fluorescence detector) has linearity (R² > 0.9974), detection limits of 0.6-4.2 ng L^-1 for liquid foods and 0.05-0.35 ng g^-1 for solid foods, recoveries of 86.2-114.9%, and intra-day/inter-day RSDs below 6.6%. The method was applied to detect PAHs in real samples, and the PAHs residue was found in honey and five solid foods. The DT-LPME method is simple, fast, green and suitable for direct extraction of analytes from both liquid and solid samples.

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.

Advanced Gel Permeation Chromatography system with increased loading capacity: Polycyclic aromatic hydrocarbons detection in olive oil as a case of study

Gel permeation chromatography (GPC) is herein used as size exclusion clean-up technique for highly sensitive and straightforward detection of Polycyclic Aromatic Hydrocarbons (PAHs) in olive oil samples. An advanced chromatographic system has been developed to isolate a series of PAHs with cancerogenic potential, including PAH4 (benzo(a)pyrene BaP, benzo(a)anthracene BaA, benzo(b)fluoranthene BbF and chrysene Chry) reported in the European Regulation. The system avails of two glass chromatographic columns and a switching valve, that allow removal of interfering analytes in olive oil without resorting to any preliminary extraction process. A seven-fold increase of the loaded sample amount versus conventional chromatographic systems (1 g vs 0.150 g) has been pursued, as well as improved PAHs detection and quantification limits (LOD-LOQ for PAH4: 0.21-0.70 ng/g for BaA, 0.26-0.86 ng/g for Chry, 0.23-0.76 ng/g for BbF, 0.32-1.06 ng/g for BaP), in accordance with the continuous need of more and more reducing these limits in food analysis by the European Regulation. The protocol developed represents a highly innovative and efficient analytical method for organic pollutants in complex biological matrices as olive oil, that can have huge impact on technology for PAHs detection in food samples, being suitable for both industrial and small-scale laboratories.

Determination of polycyclic aromatic hydrocarbons in olives exposed to three different industrial sources and in their respective oils

Atmospheric contamination of plant raw material with Polycyclic Aromatic Hydrocarbons (PAHs) helps explain their presence in edible vegetable oils. This study compared PAH contamination of Turkish olive fruits during their growing period on the tree and their respective oils from three different industrial sources (petroleum refinery, thermal power plant and heavy industry site). The method included liquid-liquid extraction solid-phase extraction for cleanup followed by HPLC with fluorescence detector. There were statistically significant differences between the three industrial sources in benzo[a]pyrene content, the sum of light, total PAHs and PAH4 (p˂0.05), but only slight differences in PAH profiles. The highest level of PAH compounds was measured in samples exposed to pollution from the petroleum refinery, nearly twice as high as samples exposed to the thermal power plant which showed the lowest contamination levels. None of the samples analysed exceeded the limits stipulated by current legislation. The transfer ratios of PAH compounds from olives to olive oil were 22.8-73.2%. This indicates that PAHs either diffuse directly from skin to oil within the fruit or transfer during oil extraction.

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 9.45 μg/kg and 11.9 μg/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 (2 μg/kg). The same batches contained a total of 19.3 μg/kg and 26.7 μg/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 (10 μg/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.

Critical review of micro-extraction techniques used in the determination of polycyclic aromatic hydrocarbons in biological, environmental and food samples

Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous environmental contaminants and their accurate determination is very important to human health and environment safety. In this review, sorptive-based micro-extraction techniques [such as Solid-Phase Micro-extraction (SPME), Stir Bar Sorptive Extraction (SBSE), Micro-extraction in Packed Sorbent (MEPS)] and solvent-based micro-extraction [Membrane-Mediated Liquid-Phase Micro-extraction (MM-LPME), Dispersive Liquid-Liquid Micro-extraction (DLLME), and Single Drop Micro-extraction (SDME)] developed for quantification of PAHs in environmental, biological and food samples are reviewed. Moreover, recent micro-extraction techniques that have been coupled with other sample extraction strategies are also briefly discussed. The main objectives of these micro-extraction techniques are to perform extraction, pre-concentration and clean up together as one step, and the reduction of the analysis time, cost and solvent following the green chemistry guidelines.

Magnetic Stirring Assisted Demulsification Dispersive Liquid⁻Liquid Microextraction for Preconcentration of Polycyclic Aromatic Hydrocarbons in Grilled Pork Samples

A simple microextraction method, magnetic stirring assisted demulsification dispersive liquid–liquid microextraction, for preconcentration of five polycyclic aromatic hydrocarbons (fluorene, phenanthrene, anthracene, fluoranthrene, and pyrene) was investigated prior to analysis by high performance liquid chromatography. In this method, a mixture of extraction solvent and disperser solvent was rapidly injected into sample solution. The magnetic stirrer agitator aided the dispersion of the extraction solvent into the sample solution. After the formation of an emulsion, the demulsifier was added, resulting in the rapid separation of the mixture into two phases. No centrifugation step was required. Several parameters affecting the extraction efficiency of the proposed method were studied, including addition of salt, kind and volume of extraction solvent, volume of demulsifier solvent, and extraction times. Under the optimum conditions, high enrichment factor, low limit of detections (LODs) and good precision were gained. The proposed method was successfully applied to analysis of polycyclic aromatic hydrocarbon residues in grilled pork samples.

Determination of benzo[α]pyrene in edible oil using tetraoxocalix[2]arene[2]triazine bonded silica SPE sorbent

Benzo[α]pyrene (BaP) is a well-known carcinogen in edible oil. In this study, a method combined solid-phase extraction (SPE) with fluorescent detection was developed using tetraoxocalix[2]arene[2]triazine sorbent (SiO₂-OCA) for the clean-up and enrichment of BaP. The interaction between SiO₂-OCA and BaP involves a donor-acceptor complex mechanism. The experimental procedure was as follows: BaP was extracted from edible oil with DMF/H₂O (9:1, v/v). Then, the ratio of DMF/H₂O was adjusted to 1:2 prior to SPE. The final concentrate was analysed using a fluorescence detector at excitation and emission wavelengths of 255 and 420 nm. The method was fully validated. The linearity was in the range of 0.1-100 μg kg^-1 with a coefficient of 0.999. The limits of detection and quantification were 0.03 and 0.1 μg kg^-1, respectively. The average recoveries were in the range of 88.0 - 122.3%. The intraday and interday precisions were 6.8% and 9.2%, respectively. Compared with other methods, the method reported in this article shows a good detection limit, high reproducibility and recovery and linearity over a broad concentration range. This established method was also applied to evaluate real samples. The concentration of six tested samples was below 5 μg kg^-1.

Characteristics of polycyclic aromatic hydrocarbons in food oils in Beijing catering services

The concentrations and characteristics of 16 polycyclic aromatic hydrocarbons (PAHs) in 48 oil samples randomly collected from 30 catering services that employ six cooking methods were quantified via high-performance liquid chromatography (HPLC). These 16 PAHs were detected in almost all of the samples. The levels of Σ16PAHs, Σ4PAHs, benzo[a]pyrene (BaP), and total BaP equivalents (ΣBaP_eq) for the six cooking methods exceeded the legal limit. The concentrations of Σ4PAHs were approximately 9.5 to 16.4 times the legal limit proposed by the European Commission (Off J Eur Union 215:4-8, 2011), and the level of BaP exceeded the national standard in China by 4.7- to 10.6-fold, particularly in oil from fried foods. Low molecular weight PAHs (LMW PAHs) were predominant in fried food oil from different catering services and accounted for 94.8 % of these oils, and the ΣBaP_eq of the high molecular weight PAHs (HMW PAHs) was 11.5-fold higher than that of the LMW PAHs. The concentrations of Σ16PAHs (3751.9-7585.8 μg/kg), Σ4PAHs (144.6-195.7 μg/kg), BaP (79.7-135.8 μg/kg), and ΣBaP_eq (231.0-265.4 μg/kg) were highest in the samples from fast food restaurants/buffets (FB), followed by those from fried food stalls (FS) and then cooking restaurants/cafeterias (RC). The results of this study suggest that the government should strengthen control and supervision of PAH contamination in food and edible oils.