Determination of parent and substituted polycyclic aromatic hydrocarbons in high-fat salmon using a modified QuEChERS extraction, dispersive SPE and GC-MS

Multivariate Optimization and Validation of a Modified QuEChERS Method for Determination of PAHs and PCBs in Grilled Meat by GC-MS

Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are recognized as carcinogens and mutagenic food contaminants that threaten public health. As for food safety aspects, control of these contaminants in processed and fatty food is necessary. In this study, eleven factors were screened by the Plackett-Burman design, and four variables were chosen to optimize with the central composite design (CCD) for the improvement of extraction and cleanup procedures of these food contaminants. The optimized variables include 5 g of sample, 2 mL mixture of 2/2/1 ethyl acetate/acetone/isooctane, 1.6 g of ammonium formate, 0.9 g of sodium chloride, and 0.25 g of sorbent Z-Sep+. A 5 min cleanup vortex time with the spike calibration curve strategy, analyzed by gas chromatography-mass spectrometry (GC-MS), led to the validated limits of quantification (LOQs) for 16 PAHs and 36 PCBs of 0.5-2 and 0.5-1 ng/g, respectively, and recoveries of 72-120%, with an average relative standard deviation (%RSD) of 17, for PAHs, and 80-120%, with an %RSD of 3, for PCBs. The method introduces excellent accuracy, precision, and efficiency, and minimizes matrix effects, and ensures a control procedure, adopted with international standards, for food authorities to determine the contaminants of interest in processed meat, and consequently, prevent food-borne disease to improve public health indices.

Microbead beating extraction of avian eggs for polycyclic aromatic compounds

Due to their relatively high trophic position and importance as a food source for many communities in the circumpolar north, seabird eggs are an important matrix for monitoring contaminant levels. In fact, many countries, including Canada, have established long-term seabird egg contaminant monitoring programs, with oil related compounds a contaminant of emerging concern for seabirds in several regions. Current approaches to measuring many contaminant burdens in seabird eggs are time-consuming and often require large volumes of solvent. Here we propose an alternative approach, based on the principle of microbead beating tissue extraction using custom designed stainless-steel extraction tubes and lids, to measure a suite of 75 polycyclic aromatic compounds (polycyclic aromatic hydrocarbons (PAHs), alkyl-PAHs, halogenated-PAHs and some heterocyclic compounds) comprising a wide-range of chemical properties. Our method was conducted in strict accordance with ISO/IEC 17025 guidelines for method validation. Accuracies for our analytes generally ranged from 70 to 120%, and intra and inter-day repeatability for most analytes were <30%. Limits of detection/quantitation for the 75 target analytes were <0.2/0.6 ng g^-1. The level of contamination in our method blanks was significantly smaller in our stainless-steel tubes/lids relative to commercially available high-density plastic alternatives. Overall, our method meets our data quality objectives and results in a notable reduction in sample processing times relative to current approaches.

The Levels of Polycyclic Aromatic Hydrocarbons and Their Derivatives in Plasma and Their Effect on Mitochondrial DNA Methylation in the Oilfield Workers

This study focuses on the components and levels of polycyclic aromatic hydrocarbons (PAHs) and their derivatives (MPAHs and OPAHs) in plasma samples from 19 oil workers, pre- and post-workshift, and their exposure-response relationship with mitochondrial DNA (mtDNA) methylation. PAH, MPAH, OPAH, and platelet mtDNA methylation levels were determined using a gas chromatograph mass spectrometer (GC-MS) and a pyrosequencing protocol, respectively. The total plasma concentrations of PAHs in mean value were, respectively, 31.4 ng/mL and 48.6 ng/mL in pre- and post-workshift, and Phe was the most abundant (13.3 ng/mL in pre-workshift and 22.1 ng/mL in post-workshift, mean value). The mean values of total concentrations of MPAHs and OPAHs in the pre-workshift were 2.7 ng/mL and 7.2 ng/mL, while in the post-workshift, they were 4.5 ng/mL and 8.7 ng/mL, respectively. The differences in the mean MT-COX1, MT-COX2, and MT-COX3 methylation levels between pre- and post-workshift were 2.36%, 5.34%, and 0.56%. Significant (p < 0.05) exposure-response relationships were found between PAHs and mtDNA methylation in the plasma of workers; exposure to Anthracene (Ant) could induce the up-regulation of the methylation of MT-COX1 (β = 0.831, SD = 0.105, p < 0.05), and exposure to Fluorene (Flo) and Phenanthrene (Phe) could induce the up-regulation of methylation of MT-COX3 (β = 0.115, SD = 0.042, p < 0.05 and β = 0.036, SD = 0.015, p < 0.05, respectively). The results indicated that exposure to PAHs was an independent factor influencing mtDNA methylation.

Optimization of micro-QuEChERS extraction coupled with gas chromatography-mass spectrometry for the fast determination of phthalic acid esters in mussel samples

In this study, a new miniaturized version of the analytical method based on the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) technique using Florisil in the cleanup step for extracting six phthalic acid esters (PAEs) in mussel samples was developed by using a design of experiments. For this purpose, 1.5 mL of ultrapure water and later, 1.5 mL of acetonitrile were added to 0.1 g of the lyophilized sample, followed by 0.3 g of a commercial extraction salt packet (magnesium sulfate, sodium chloride, sodium citrate dihydrate, and sodium hydrogencitrate sesquihydrate). The recovered extract was purified using 0.1 g of Florisil. The final extract was evaporated and reconstituted in 1 mL of hexane. The six phthalates were determined by a GC-MS (SIM) system. The whole method was validated at two concentration levels. Recoveries ranged from 79% to 108%. Reproducibility in terms of coefficients of variation was between 4.9% and 12.1%. The limits of quantification of the whole method were between 0.53 and 38.0 μg per kg dry weight. Five mussel samples coming from the Galician Rías were analysed using this method. Except for three of the five samples where DnOP (di-n-octyl phthalate) was below the limit of quantification, all PAEs were found in concentrations that ranged between 1.99 and 372.7 μg per kg dry weight.

1-Nitropyrene exposure induces mitochondria dysfunction and impairs oocyte maturation in mice

Oocyte quality is essential for a successful pregnancy. 1-Nitropyrene (1-NP) is a widely distributed pollutant in the environment and is well-known for its mutagenicity and carcinogenicity. However, whether 1-NP has toxic effects on mammalian oocyte quality remains unknown. In the present study, we focused on the effect of 1-NP on oocyte maturation using mouse oocytes as an in vitro model. Our study showed that 1-NP exposure disrupted the meiotic spindle assembly and caused chromosome misalignment, further impaired first polar body extrusion, and significantly decreased the fertilization capability in mouse oocytes. Further investigation showed that the mitochondrial membrane potential (MMP) and ATP levels were decreased, and the expression of genes encoding components of the mitochondrial respiratory chain was inhibited in 1-NP exposed oocytes. Meanwhile, 1-NP exposure increased the levels of reactive oxygen species (ROS), inhibited the expression of genes encoding antioxidant enzymes, and increased the frequency of early apoptotic oocytes. Overall, our data suggest that 1-NP exposure disrupts mitochondrial function and intracellular redox balance, ultimately impairing oocyte maturation. These findings reveal the adverse effect of 1-NP exposure on oocyte quality.

Green synthesis of phloroglucinol-urotropine porous polymer: Ingenious miniaturized solid phase extraction for efficient purification and determination of polycyclic aromatic hydrocarbons in lotus roots

Polycyclic aromatic hydrocarbons (PAHs) posed a serious threat to food safety and human health due to long-term emission. In this work, a new method was established using phloroglucinol-urotropine porous polymer (PU-PP) in a pipette tip for solid phase extraction (PT-SPE) for the first time and used prior to determination of four PAHs (phenanthrene, anthracene, fluoranthene, and pyrene) in lotus roots. Synthesis of the PU-PP adsorbent was green compared with alternatives; urotropine was used as a cross-linker and ethanol-water as the solvent. PU-PP-based PT-SPE had the advantages of low solvent consumption, good purification, practicability, stability, and low-cost. The proposed pre-purification method offered low limits of detection (0.09-0.28 ng/g) and good recoveries (84.6-114.3 %, RSDs ≤ 5.6 %) for determination of the four PAHs, which were detected at trace concentrations in samples. This new method provides an alternative for monitoring trace pollutants in aquatic plant ingredients.

Analysis of four polycyclic aromatic hydrocarbons in plant-based food supplements-results of a collaborative study

The determination of carcinogenic polycyclic aromatic hydrocarbons (PAHs) in food supplements is challenging, especially due to the presence of other e.g. heterogeneous PAH-like compounds in the matrix. A collaborative study with 12 participants was conducted in order to assess performance characteristics of a fast method intended to analyse the four regulated PAHs (PAH 4) benzo[b]fluoranthene [BbF], benz[a]anthracene [BaA], chrysene [CHR] and benzo[a]pyrene [BaP] in five different plant-based food supplements in the form of capsules, powder, and tablets. The principle of the method includes the extraction of PAHs with ethyl acetate: cyclohexane followed by a two-step SPE cleanup and final analysis by GC-MS or LC-FLD. The regulated maximum level for BaP is 10 µg/kg and, for the PAH 4, 50 µg/kg. Accordingly, the method was validated for the regulated PAH 4 analytically challenging concentration range from 2.5 µg/kg to 6.9 µg/kg. The performance criteria for the method set in European Regulation No 333/2007 for the overall repeatability, reproducibility (HorRat values below 2), and recovery (range 50-120%) were fulfilled. Based on the statistical evaluation of the results, it was concluded that the method is a suitable alternative to existing methods and should be studied for additional matrices.

Assessing integrated biomarkers of triplefin fish Forsterygion capito inhabiting contaminated marine water - A multivariate approach

The presence of multiple chemicals in aquatic ecosystems makes evaluation of their real impact on the biota difficult. Integrated biomarkers are therefore needed to evaluate how these chemicals contribute to environmental degradation. The aims of the present study were to evaluate responses to and effects of marine pollution using a series of biomarkers through multivariate analyses. Transcriptional responses of cyp1a (cytochrome P450), mt (metallothionein), vtg (vitellogenin) and cyp19b (cytochrome P450 aromatase); branchial and hepatic histological alterations; and Fulton condition factors (CF) were evaluated, as well as the metals and polycyclic aromatic hydrocarbons present in Forsterygion capito in Auckland, New Zealand. Sites were selected along a contamination gradient: four highly contaminated sites and four less contaminated. Molecular responses with a higher relative expression of the mt and cyp1a genes were detected at a highly contaminated site (Panmure). Several histological lesion types were found in the livers of fish inhabiting both types of sites, but gill lesions were present primarily at highly contaminated sites. In terms of general health status, the lowest CF values were overwhelmingly found in fish from the same site (Panmure). The multivariate approach revealed that telangiectasia and hyperplasia were associated with the presence of chemicals, and these showed negative associations with the CF values, with fish from three highly contaminated sites being most affected. In conclusion, the multivariate approach helped to integrate these biological markers in this blennioid fish, thus providing a more holistic view of the complex chemical mixtures involved. Future studies should implement these analyses.

Chromatographic techniques for the analysis of organophosphate pesticides with their extraction approach: a review (2015-2020)

In agriculture, a wide range of OPPs has been employed to boost crop yield, quality, and storage life. However, due to the ever-increasing population and rapid urbanization, pesticide use has surged in recent years. These compounds are exceedingly poisonous to humans, and despite the fact that specific legislation prohibits their use, the frequency of toxic and/or fatal incidents, as well as current statistics, suggest that they are currently accessible. As a result, determining the exposure to these substances as well as their detection (and that of their metabolites) in different types of exposed samples has become a hot issue in terms of quality and safety concerns. However, developing tools for the evaluation of these substances is a critical challenge for laboratories. Various chromatographic-based methods reported in the period of 2015-2020 have been developed, which are summarized and critically reviewed in this article, including the extraction of the target OPPs from different kinds of matrices. A comparison among the extraction and analysis techniques has been made in the current review article.

Critical Assessment of Clean-Up Techniques Employed in Simultaneous Analysis of Persistent Organic Pollutants and Polycyclic Aromatic Hydrocarbons in Fatty Samples

Interference of residual lipids is a very common problem in ultratrace analysis of contaminants in fatty matrices. Therefore, quick and effective clean-up techniques applicable to multiple groups of analytes are much needed. Cartridge and dispersive solid-phase extraction (SPE and dSPE) are often used for this purpose. In this context, we evaluated the lipid clean-up efficiency and performance of four commonly used sorbents—silica, C18, Z-Sep, and EMR-lipid—for the determination of organic pollutants in fatty fish samples (10%) extracted using ethyl acetate or the QuEChERS method. Namely, 17 polychlorinated biphenyls (PCBs), 22 organochlorine pesticides (OCPs), 13 brominated flame retardants (BFRs), 19 per- and polyfluoroalkyl substances (PFAS), and 16 polycyclic aromatic hydrocarbons (PAHs) were determined in this study. The clean-up efficiency was evaluated by direct analysis in real time coupled with time-of-flight mass spectrometry (DART-HRMS). The triacylglycerols (TAGs) content in the purified extracts were significantly reduced. The EMR-lipid sorbent was the most efficient of the dSPE sorbents used for the determination of POPs and PAHs in this study. The recoveries of the POPs and PAHs obtained by the validated QuEChERS method followed by the dSPE EMR-lipid sorbent ranged between 59 and 120%, with repeatabilities ranging between 2 and 23% and LOQs ranging between 0.02 and 1.50 µg·kg⁻¹.

The loss and fate of BaA, Chr, BbF, and BaP (PAH4) tracked by stable isotope during frying

The objective of this work was to accurately quantify the loss of benzo(a)anthracene, chrysene, benzo(b)fluoranthene, and benzo(a)pyrene (PAH4) and investigate the fate of the lost PAH4 into their derivatives during frying. Stable isotopes (PAH4-d12) were used to simulate the loss and track the conversion of PAH4. The results showed that the rate of loss of PAH4-d12 increased with the increase of frying temperature and the loss rate of benzo(a)pyrene-d12 was the largest, indicating that benzo(a)pyrene had the strongest chemical reactivity during frying. Moreover, the identification of five PAH4 derivatives has confirmed the conversion of lost PAH4. Finally, the loss of PAH4 during frying positively correlated with the oxidation of oil, and a conversion mechanism of PAHs to derivatives was proposed. This work directly proved the loss and conversion of PAH4 and provided a comprehensive perspective for studying the changes in PAH4 during frying.

Development and validation of a micro-QuEChERS method with high-throughput enhanced matrix removal followed with UHPLC-QqQ-MS/MS for analysis of raspberry ketone-related phenolic compounds in adipose tissues

Raspberry ketone (RK) is a major flavor compound in red raspberries, and it has been marketed as a popular weight-loss dietary supplement with high potential in accumulating in fatty tissues. However, challenges in extracting and characterizing RK and its associated phenolic compounds in fatty tissues persist due to the complex matrix effect. In this work, we reported a high-throughput sample preparation method for RK and 25 related phenolic compounds in white adipose tissues using an improved micro-scale QuEChERS (quick, efficient, cheap, easy, rugged and safe) approach with enhanced matrix removal (EMR)-lipid cleanup in 96-well plates, followed by UHPLC-QqQ-MS/MS analysis. The absolute recovery was 73-105% at the extraction step, and achieved 71-96% at the EMR cleanup step. The EMR cleanup removed around 66% of total lipids in the acetonitrile extract as profiled by UHPLC-QTOF-MS/MS. The innovative introduction of a reversed-phase C18 sorbent into the extract significantly improved the analytes' recovery during SpeedVac drying. The final accuracy achieved 80-120% for most analytes. Overall, this newly developed and validated method could serve as a powerful tool for analyzing RK and related phenolic compounds in fatty tissues.

Mapping carcinogen exposure across urban fire incident response arenas using passive silicone-based samplers

Carcinogens are emitted in significant quantities at fire scenes and are a major contributor in the increased cancer risk observed in firefighters when compared to the general population. A knowledge gap exists in the current understanding of the distribution of these toxic compounds within a localized fire incident response arena. Here, we employ stationary silicone-based passive samplers at controlled live fire trainings to evaluate the deposition behavior of polyaromatic hydrocarbons (PAHs) emitted by fires. Our findings indicate significantly greater total PAH exposure in fires fueled by biomass and wood compared to fires burning cleaner fuels, such as propane. A 22% increase in total PAH deposition and a 68% increase in high molecular weight PAH deposition was recorded for biomass fueled fires compared to propane fueled fires. Furthermore, we observe that heavier molecular weight PAHs exhibit a pronounced deposition front within a certain radius of the hot zone, whereas low molecular weight PAHs are more uniformly distributed throughout the area. These findings highlight that the warm zones and cold zones of fire situations yield elevated levels of carcinogen exposure to first responders within them. We anticipate that these findings will help inform decisions made by emergency personnel when evaluating risk for the hot zone, warm zone, and cold zone of urban fires helping ease the carcinogenic risk experienced.

The pesticide residue analysis in commodities with high content of chlorophyll based on the quick, easy, cheap, effective, rugged, and safe method: A review

In multiresidue analysis, the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) is one of the most popular techniques routinely used by researchers during pesticide analysis of food and vegetable samples. Originally, the QuEChERS method was developed for analysis of pesticide residues from fruits and vegetables, but rapidly gained popularity in the extraction of analytes from different matrices. This analytical approach shows several advantages over traditional extraction techniques: it requires lower sample and solvent amounts while shortening the time of sample preparation. However, it presents some limitations for complex matrices such as those containing high amounts of chlorophyll. To overcome the problem of strong matrix effect and influence of interferences, different approaches are applied. Most are concerning modifications of the cleanup step, that is, sorbent type and its amount. Optimization of other parameters, such as sample size, hydration level, extraction solvent, and buffering, also has an impact on overall performance. Combining proper sample preparation with modern highly sensitive and selective detection techniques enables receiving desired limits of quantification. This article presents an overview of strategies employed by researchers for analysis of green, high chlorophyll content commodities and results obtained in their studies.

New approaches to reduce sample processing times for the determination of polycyclic aromatic compounds in environmental samples

This study validates two approaches to streamlining the processing of sediment and biota for a suite of polycyclic aromatic compounds (PACs) with a wide range of chemical properties, including polycyclic aromatic hydrocarbons (PAHs) and alkyl-PAHs (APAHs), and a new class of environmental contaminants, halogenated PAHs (HPAHs). One method is based on one-step in situ extraction/cleanup using accelerated solvent extraction (ASE) in which a mixture of copper, deactivated alumina and silica gel were added directly to the ASE cell along with sample; the second technique is based on dispersive solid phase extraction (dSPE) using alumina/silica for cleanup of biota samples to augment conventional ASE extraction combined with gel permeation chromatography. Validation protocols were performed in accordance with the ISO/IEC 17025 guidelines, whereby method performance characteristics, i.e., accuracy, precision, linearity, limits of detection and ruggedness, were evaluated. Accuracies generally ranged from 70 to 120% for the in situ ASE method and 70-100% for the dSPE technique. Limits of detection/quantitation for the 45 target analytes for in situ ASE and dSPE methods were determined to be < 2.5/8 pg μL^-1, and < 20/60 pg μL^-1, respectively. Intra- and inter-day repeatability for both methods were < 25% except for 1 APAH which had an inter-day precision of 35% using the dSPE method. Neither method was affected by any of the purposeful changes attempted which implies that both methods are robust. Results of our validation studies showed excellent data quality for both methods in addition to achieving a reduction in sample processing times.

An Integrated Strategy for Purification by Combining Solid-Phase Extraction with Dispersive-Solid-Phase Extraction for Detecting 22 Pesticides and Metabolite Residues in Fish

A robust isotope-labeled internal standard method was established for the detection of 22 pesticides and metabolite residues in four kinds of fish; two were from freshwater fish, and two were from marine fish. Pesticides with wide application possibilities in rice in China, strong leaching to water, or high bioconcentration factors (BCF) in fish were selected. The samples were extracted with 1% acetic acid-99% acetonitrile. The extracts were first purified by solid-phase extraction (PEP-plus), cleaned with dispersive-solid-phase extraction (PSA and C18), and finally analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results showed that good linearities for the target compounds were observed in the range of 0.1-100 ng/mL, and the correlation coefficient (R²) of each compound was greater than 0.99. The recoveries of the method were within 70-120% with RSDs <20% at three different spiked concentration levels (0.5, 5, and 100 ng/g). The quantitative limit of the method was 0.5-5 ng/g. The method is shown to be sensitive and accurate and can meet the demands for the quantitative analysis of pesticides in fish.

Determination of 15 + 1 European Priority Polycyclic Aromatic Hydrocarbons in Smoked Meat Products by Saponification/Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry

A method for the determination of 15 + 1 European priority polycyclic aromatic hydrocarbons (EUPAHs) in smoked meat samples by saponification/solid-phase extraction and gas chromatography-mass spectrometry has been developed. Both saponification and solid-phase extraction conditions were optimized, which lead to shorter sample preparation time and excellent sensitivity and selectivity. The optimal saponification condition for the lipid extract of 5.00 g smoked food sample was 5 mL KOH (1.5 mol/L)-ethanol at 70°C for 5 min, and the shorter alkaline treatment time avoided the loss of volatile EUPAHs such as Benzo[c]fluorene. All the EUPAHs showed good linearity in the range between 5.0 and 50.0 ng/mL with correlation coefficients between 0.997 and 1.00. The estimated LODs for the EUPAHs were 0.15-0.30 μg/kg, while the LOQs were 0.50-1.0 μg/kg. The three spiking levels of EUPAHs were 1.0, 2.0 and 5.0 μg/kg, and the average recovery was between 75.2 and 99.6%, while the RSD were 2.3-12.4%. This sensitive and rapid method was successfully applied to smoked meat samples from Zhejiang Province of China, and the results revealed the presence of 13 EUPAHs. Benzo[a]pyrene (BaP) was found in 19 out of 20 samples, with concentration ranging from 0.51 to 4.57 μg/kg. The sum of concentrations of PAH4 (summation of benzo(a)pyrene, chrysene, benzo(a)anthracene, and benzo(b)fluoranthene) were 2.40-53.56 μg/kg.

Oral and Dermal Bioavailability Studies of Polycyclic Aromatic Hydrocarbons from Soils Containing Weathered Fragments of Clay Shooting Targets

The relative oral bioavailability and dermal absorption of chemical substances from environmental media are key factors that are needed to accurately estimate site-specific risks and manage human exposures. This study evaluated the in vivo relative oral bioavailability and in vitro dermal absorption of several polycyclic aromatic hydrocarbons (PAHs) found in soils collected from two formerly used Department of Defense sites impacted by weathered fragments of clay shooting targets. Concentrations of individual carcinogenic PAHs in the ≤250 μm fraction of soil ranged from approximately 0.1 to 100 mg/kg. A novel sample preparation method was developed to produce accurate and precise test diets for oral studies. The resulting test diets showed consistent concentrations of PAHs in soil- and soil-extract-amended diets and a consistent PAH concentration profile. Mean oral relative bioavailability factors (RBAFs) and dermal absorption fractions (ABS_d) for benzo(a)pyrene ranged from 8 to 14% and 0.58 to 1.3%, respectively. Using the RBAF and ABS_d values, measured here, for benzo(a)pyrene in USEPA's regional screening level equations yields concentrations for residential soils that are approximately eight times higher than those when default values are used (e.g., 9.6 vs 1.2 mg/kg at a target excess risk of 1 × 10^-5).

Development of a new generic extraction method for the analysis of pesticides, mycotoxins, and polycyclic aromatic hydrocarbons in representative animal feed and food samples

Various generic extraction methods have been used to determine pesticide residues, mycotoxins, and polycyclic aromatic hydrocarbons (PAHs) in food and animal feed to ensure consumer safety. However, these methods cannot extract all relevant compounds at an acceptable rate of recovery. This study presents a new extraction method. This new method facilitated the identification of 231 compounds, including 196 pesticides, 11 mycotoxins, and 24 PAHs over a broad range of polarities. These compounds were identified in various sample matrices, including those that are lipid-rich. The processed sample is first extracted with water, acetonitrile, formic acid, and heptane. The addition of ammonium formate results in separation into three phases and enables analysis of the aqueous phase. Solid-phase extraction clean-up procedures were performed as necessary followed by analysis by liquid or gas chromatography and mass spectrometry. Analyte recoveries were typically in the range of 70 - 120% with relative standard deviations below 20%.

Analysis and formation of polycyclic aromatic hydrocarbons and cholesterol oxidation products in thin slices of dried pork during processing

This study aims to determine toxic compounds polycyclic aromatic hydrocarbons (PAHs) and cholesterol oxidation products (COPs) in thin slices of dried pork as affected by different flavorings and roasting temperature treatments through employing a QuEChERS method coupled with gas chromatograph-tandem mass spectrometer (GC-MS/MS) and gas chromatograph-mass spectrometer (GC-MS), respectively. By employing this method, high accuracy and precision was attained for freeze-dried pork hind leg sample. Following addition of 8 different flavorings with roasting temperature at 120, 160, and 200 °C, the levels of total COPs and PAHs in thin slices of dried pork followed a temperature-dependent increase during roasting, which was further confirmed by principle component analysis. High level of soy sauce or sugar inhibited COP formation, while the low-level minimized PAH formation in thin slices of dried pork during roasting. Sugar was more effective in inhibiting COP formation while soy sauce was more efficient in reducing PAH formation.

Automated micro-solid-phase extraction clean-up of polycyclic aromatic hydrocarbons in food oils for analysis by gas chromatography-orbital ion trap mass spectrometry

Food can contain unwanted compounds and need to be analyzed for compounds like carcinogenic polycyclic aromatic hydrocarbons to ensure consumer safety. The analytes need to be extracted from the sample matrix and cleaned-up to enable detection. However, established methods for clean-up are labor intensive and have a high expenditure on organic solvents. Here, we show a newly developed micro-solid-phase extraction cartridge method to automate the clean-up for analysis of polycyclic aromatic hydrocarbons in sunflower oil using gas chromatography with quadrupole-orbitrap mass spectrometry with a TriPlus autosampler. This automated micro-solid-phase extraction cartridge method needs only 4 μL of vegetable oil sample and requires only 360 μL acetonitrile for elution, and, therefore, it needs only small amounts of organic solvent. Two different micro-solid-phase extraction cartridge methods were developed, one using two commercially available cartridges with florisil and octadecylsilane/Z-Sep/CarbonX, and the other method using one commercially available cartridge with florisil followed by one self-made cartridge with octadecylsilane/Z-Sep. The latter method showed successful lipid removal and was further validated for 22 of 24 polycyclic aromatic hydrocarbon compounds in sunflower oil at a spiked level of 1090 μg/kg with recoveries ranging from 53 to 118% and relative standard deviation below 22%. This method shows promising short-time clean-up with low expenditure of solvents.

Sorption kinetics of parent and substituted PAHs for low-density polyethylene (LDPE): Determining their partition coefficients between LDPE and water (KLDPE) for passive sampling

Low-density polyethylene (LDPE) has been widely used as a sorbent for passive sampling of hydrophobic organic contaminants (HOCs) in aquatic environments. However, it has seen only limited application in passive sampling for measurement of freely dissolved concentrations of parent and substituted PAHs (SPAHs), which are known to be toxic, mutagenic and carcinogenic. Here, the 16 priority PAHs and some typical PAHs were selected as target compounds and were simultaneously determined by gas chromatography-mass spectrometer (GC-MS). Some batch experiments were conducted in the laboratory to explore the adsorption kinetics of the target compounds in LDPE membranes. The results showed that both PAHs and SPAHs could reach equilibrium status within 19-38 days in sorption kinetic experiments. The coefficients of partitioning between LDPE film (50 μm thickness) and water (K_LDPE) for the 16 priority PAHs were in good agreement with previously reported values, and the values of K_LDPE for the 9 SPAHs are reported in this study for the first time. Significant linear relationships were observed, i.e., log K_LDPE = 0.705 × log K_OW + 1.534 for PAHs (R² = 0.8361, p < 0.001) and log K_LDPE = 0.458 × log K_OW + 3.092 for SPAHs (R² = 0.5609, p = 0.0077). The selected LDPE film was also proven to meet the condition of "zero sink" for the selected target compounds. These results could provide basic support for the configuration and in situ application of passive samplers.

Hepatobiliary Analyses Suggest Chronic PAH Exposure in Hakes (Urophycis spp.) Following the Deepwater Horizon Oil Spill

Prior to the Deepwater Horizon oil spill, we lacked a comprehensive baseline of oil contamination in the Gulf of Mexico's sediments, water column, and biota. Gaps in prespill knowledge limit our ability to determine the aftereffects of the Deepwater Horizon blowout or prepare to mitigate similar impacts during future oil spill disasters. We examined spatiotemporal differences in exposure to and metabolism of polycyclic aromatic hydrocarbons (PAHs) in 2 hake species (Urophycis spp.) to establish a current baseline for these ecologically important, abundant, and at-risk demersal fishes. Gulf hake (Urophycis cirrata) and southern hake (Urophycis floridana) were collected throughout the Gulf of Mexico during extensive longline surveys from 2012 to 2015. Analyses of biliary PAH metabolites and liver PAH concentrations provided evidence of exposures to di- and tricyclic compounds, with the highest concentrations measured in the northern Gulf of Mexico. Species-specific differences were not detected, but temporal trends observed in biliary PAHs suggest a decrease in acute exposures, whereas increasing liver PAHs suggest chronic exposures marked by greater assimilation than metabolism rates. To our knowledge, the present study provides the first multitissue contaminant analyses, as well as the most exhaustive biometric analyses, for both gulf and southern hakes. Though sources of exposure are complex because of multiple natural and anthropogenic PAH inputs, these results will facilitate the development of much needed health metrics for Gulf of Mexico benthos. Environ Toxicol Chem 2019;38:2740-2749. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Distribution of petrogenic polycyclic aromatic hydrocarbons (PAHs) in seafood following Deepwater Horizon oil spill

A community-based participatory research was utilized to address the coastal community's concern regarding Deepwater Horizon oil contamination of seafood. Therefore, we analyzed polycyclic aromatic hydrocarbons (PAHs), major toxic constituents of crude oil, in the seafood collected from gulf coast (Louisiana, Alabama and Mississippi) during December 2011-February 2014. PAHs were extracted from edible part of shrimp, oysters, and crabs by the QuEChERS/dsPE procedure and analyzed by gas chromatography-mass spectrometry. The total PAHs data were further analyzed using the General Linear Mixed Model procedure of the SAS (Version 9.3, SAS Institute, Inc., Cary, NC) statistical software. Brown shrimp showed statistically significant differences in PAHs levels with respect to time and locations while white shrimp showed differences at various time points. PAHs levels in oyster and crab samples were not statistically different at the Type I error of 0.05. Overall, the PAHs levels are far below FDA levels of concern for human consumption.

Assessment of preservative migration from wood using a soil sachet method

The ability of standard soils to capture heavy metals or polycyclic aromatic hydrocarbons (PAHs) from ammoniacal copper zinc arsenate (ACZA)- or creosote-treated wood, respectively, was assessed using pressure-treated posts immersed in a freshwater pond. The soil, in heat-sealed, permeable plastic mesh sachets, was able to intercept copper, zinc, arsenic, and PAHs migrating from the posts. Chemical levels were much higher immediately adjacent to the posts and declined with distance from the posts. Metals were consistently detected around ACZA-treated posts, while 10 of the 16 EPA priority pollutants were detected in at least one sachet embedded around creosote-treated posts at each sampling point. These results were consistent with traditional sediment sampling methods. The primary advantages of the sachets were their consistency in terms of soil characteristics and the ease with which they could be retrieved from the pond. Further studies are planned to better understand the role of soil characteristics in the sachets on the ability to capture migrating preservatives.

Comparison of extraction techniques for polycyclic aromatic hydrocarbons from lichen biomonitors

Lichens are useful biomonitors for atmospheric polycyclic aromatic hydrocarbons (PAHs). Different sample preparation techniques were explored in this regard, including ultrasound-assisted solvent extraction, microwave-assisted extraction, Soxhlet, and the quick, easy, cheap, effective, rugged, and safe (QuEChERS) technique. It was found that a QuEChERS technique using hexane:acetone (1:1, v/v), never reported before for application to lichens, provided the best recoveries of internal standards, the highest total peak area for all PAHs of interest, and %RSDs comparable with the other preparation techniques tested. The optimized sample preparation technique was found to be a comparatively fast method (45 min), with good recoveries (96%), using less solvents and minimal energy consumption. Strong matrix effects were found: both strong enhancement (for the lighter PAHs) and strong suppression (for the heavier PAHs). The use of matrix-matched standards is thus imperative for the accurate determination of PAH concentrations in the lichen samples. Graphical abstract "Note: This data is mandatory. Please provide."

Differential exposure to organophosphate flame retardants in mother-child pairs

BACKGROUND

Humans are ubiquitously exposed to flame retardants, including organophosphate esters (OPEs), through direct contact with consumer products or exposure through household dust. Children are at increased risk because of their proximity to dust, hand-to-mouth activity, and the importance of childhood as a critical period in neurodevelopment.

OBJECTIVES

To quantify differences in exposure levels between mothers and children (three to six years of age), we analyzed urinary metabolites of OPEs. We additionally assessed the ability of silicone wristbands (measuring ambient exposure) to predict urinary metabolite concentrations.

METHODS

We selected 32 mother and child dyads from an existing cohort. Participants provided baseline urine samples and wore wristbands for one week. After the first week, they returned their wristbands and provided a second urine sample. During the second week, participants wore a second wristband that they returned at the end of week two with a third and final urine sample.

RESULTS

We found significantly higher levels of bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) (p < 0.001) and lower levels of bis(1-chloro-2-isopropyl) 1-hydroxy-2-propyl phosphate (BCIPHIPP) (p < 0.001) in children's urine samples compared to mothers' samples at baseline. We found that triphenylphosphate (TPHP), tris(1,3-dichloroisopropyl) phosphate (TDCIPP), and tris(1-chloro-2-propyl) phosphate (TCIPP) measured in wristbands predicted their respective metabolite levels in urine.

CONCLUSION

Children had higher levels than mothers for two of six flame retardant metabolites measured in urine. Generally, wristband measurements positively predicted internal dose. As little is known about the health effects of OPEs on child development, future research is needed to determine the impact of differential exposure.

Simultaneous Determination of 18 Polycyclic Aromatic Hydrocarbons in Daily Foods (Hanoi Metropolitan Area) by Gas Chromatography⁻Tandem Mass Spectrometry

Polycyclic aromatic hydrocarbons (PAHs)-a large group of organic compounds-are extremely hazardous to human health. In this study, the 198 samples from six groups of daily food products in the Hanoi metropolitan area were collected and prepared by the QuEChERS sample treatment technique. The detection and identification of PAHs were obtained by gas chromatography⁻tandem mass spectrometry (GC⁻MS/MS) determination. The results demonstrated that the recovery of PAH compounds ranged approximately between 71% and 110% when the solvent evaporation condition was optimized using the nitrogen gas at a low temperature (1 °C). The in-house method was validated in terms of linearity, extractive condition, repeatability, recovery, limit of detection (LOD), and limit of quantification (LOQ). The ranges of average PAH levels were 9.3⁻9.6 µg/kg (for instant noodles), 0.22⁻2.48 µg/kg (for cakes) 0.91⁻4.83 µg/kg (dried vegetables), 5.14⁻23.32 µg/kg (teas), 4.82⁻24.35 µg/kg (coffees), and 1.43⁻25.2 µg/kg (grilled meats). The results indicated that the total concentrations of residual PAHs and benzo(a)pyrene in the instant noodles and grilled meat samples surpassed the maximum limits tolerated by the European Commission (35 µg/kg and 5 µg/kg, respectively) in many investigated samples.

Pharmacokinetics of [14C]-Benzo[a]pyrene (BaP) in humans: Impact of Co-Administration of smoked salmon and BaP dietary restriction

Benzo[a]pyrene (BaP), a polycyclic aromatic hydrocarbon (PAH), is a known human carcinogen. In non-smoking adults greater than 95% of BaP exposure is through diet. The carcinogenicity of BaP is utilized by the U.S. EPA to assess relative potency of complex PAH mixtures. PAH relative potency factors (RPFs, BaP = 1) are determined from high dose animal data. We employed accelerator mass spectrometry (AMS) to determine pharmacokinetics of [¹⁴C]-BaP in humans following dosing with 46 ng (an order of magnitude lower than human dietary daily exposure and million-fold lower than animal cancer models). To assess the impact of co-administration of food with a complex PAH mixture, humans were dosed with 46 ng of [¹⁴C]-BaP with or without smoked salmon. Subjects were asked to avoid high BaP-containing diets and a 3-day dietary questionnaire given to assess dietary exposure prior to dosing and three days post-dosing with [¹⁴C]-BaP. Co-administration of smoked salmon, containing a complex mixture of PAHs with an RPF of 460 ng BaP_eq, reduced and delayed absorption. Administration of canned commercial salmon, containing very low amounts of PAHs, showed the impacts on pharmacokinetics were not due to high amounts of PAHs but rather a food matrix effect.

Ionization of Gas-Phase Polycyclic Aromatic Hydrocarbons in Electrospray Ionization Coupled with Gas Chromatography

Herein, gas-phase polycyclic aromatic hydrocarbons (PAHs) as nonpolar compounds were ionized to protonated molecular ions [M + H]⁺ without radical cations and simultaneously analyzed using gas chromatography (GC)/electrospray ionization (ESI)-tandem mass spectrometry (MS/MS). The ionization profile, dissociation, and sensitivity were first investigated to understand the significant behavior of gas-phase PAHs under ESI. The formation of protonated molecular ions of PAHs was distinguished according to the analyte phase and ESI spray solvents. The protonated PAHs exhibited characteristic dissociations, such as H-loss, H₂-loss, and acetylene-loss, via competition of internal energy. In addition, GC/ESI-MS/MS resulted in relatively lower concentration levels (better sensitivity) for the limits-of-detection (LODs) of PAHs than liquid chromatography (LC)/ESI-MS/MS, and it seems to result from the characteristic ionization mechanism of the gas-phase analyte under ESI. Furthermore, the LODs of gas-phase PAHs depended on molecular weight and proton affinity (PA). Consequently, we demonstrated the relationship among the analyte phases, sensitivities, and structural characteristics (molecular weight and PA) under ESI. The gas-phase PAHs provided enhanced protonation efficiency and sensitivity using GC/ESI-MS/MS, as their molecular weight and PA increased. Based on these results, we offered important information regarding the behavior of gas-phase analytes under ESI. Therefore, the present GC/ESI-MS/MS method has potential as an alternative method for simultaneous analysis of PAHs.

Application of QuEChERS for Determining Xenobiotics in Foods of Animal Origin

The use of pesticides and veterinary drugs results in the appearance of residues of xenobiotics in foods. Thus, several methods have been developed for monitoring them; however, most are tedious and expensive. By contrast, the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology involves a microextraction that yields small samples and has been applied for the analysis of various xenobiotics including pesticides, antibiotics, and mycotoxins. QuEChERS has shown advantages over other techniques including fast sample preparation, reduced needs for reagents and labware, and versatility. This approach allows the simultaneous determination of pesticides with various polarities and volatilities and can be easily modified for the analysis of a wide range of xenobiotics in various matrices including animal products rich in fat. Nevertheless, to attain high recoveries, the extraction, cleanup, and concentration steps have to be optimized according to the target compounds and matrix. Hence, QuEChERS is a promising and environmentally friendly methodology for the high-throughput routine analysis of xenobiotics in animal products. This review focuses on the application of QuEChERS to foods of animal origin and describes recent developments for the optimization of the analysis of veterinary drugs, pesticides, polycyclic aromatic hydrocarbons, and other compounds of concern.

Development of a QuEChERS-Based Method for Determination of Carcinogenic 2-Nitrofluorene and 1-Nitropyrene in Rice Grains and Vegetables: A Comparative Study with Benzo[a]pyrene

Nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) are ubiquitous environmental pollutants attracting increasing attention because of their potent mutagenicity to humans. Previous studies of nitro-PAHs focused on investigating their formation mechanisms and detecting them in atmospheric environment; however, few studies have reported their occurrence in food samples, and regulations on nitro-PAHs are still lacking. We report in this study the development and application of a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for determination of nitro-PAHs in rice and vegetable samples. Analysis of the collected samples by the validated method revealed 1-nitropyrene and 2-nitrofluorene were widespread food contaminants. A comparative study with benzo[a]pyrene, the commonly used marker for PAH exposure, showed that carcinogenic nitro-PAHs existed in rice and vegetables at similar concentrations. Dietary exposure risk, which was estimated based on the surveillance data, suggested 3.28-5.03 ng/kg/day of nitro-PAHs exposure for Hong Kong citizens from rice grains and vegetables.

Communicating Results of a Dietary Exposure Study Following Consumption of Traditionally Smoked Salmon

One expectation of community-based participatory research (CBPR) is participant access to study results. However, reporting experimental data produced by studies involving biological measurements in the absence of clinical relevance can be challenging to scientists and participants. We applied best practices in data sharing to report the results of a study designed to explore polycyclic aromatic hydrocarbons absorption, metabolism, and excretion following consumption of traditionally smoked salmon by members of the Confederated Tribes of the Umatilla Indian Reservation (CTUIR). A dietary exposure study was developed, in which nine Tribal members consumed 50 g of traditionally smoked salmon and provided repeated urine samples over 24 hours. During recruitment, participants requested access to their data following analysis. Disclosing data is an important element of CBPR and must be treated with the same rigor as that given to the data analysis. The field of data disclosure is relatively new, but when handled correctly can improve education within the community, reduce distrust, and enhance environmental health literacy. Using the results from this study, we suggest mechanisms for sharing data with a Tribal community.

Using silicone wristbands to evaluate preschool children's exposure to flame retardants

Silicone wristbands can be used as passive sampling tools for measuring personal environmental exposure to organic compounds. Due to the lightweight and simple design, the wristband may be a useful technique for measuring children's exposure. In this study, we tested the stability of flame retardant compounds in silicone wristbands and developed an analytical approach for measuring 41 flame retardants in the silicone wristband in order to evaluate exposure to these compounds in preschool-aged children. To evaluate the robustness of using wristbands to measure flame retardants, we evaluated the stability of 3 polybrominated diphenyl ethers (BDEs), and 2 organophosphate flame retardants (OPFRs) in wristbands over 84 days and did not find any evidence of significant loss over time at either 4 or -20°C (p>0.16). We recruited a cohort of 92 preschool aged children in Oregon to wear the wristband for 7 days in order to characterize children's acceptance of the technology, and to characterize their exposure to flame retardants. Seventy-seven parents returned the wristbands for analysis of 35 BDEs, 4 OPFRs, and 2 other brominated flame retardants although 5 were excluded from the exposure assessment due to protocol deviations (n=72). A total of 20 compounds were detected above the limit of quantitation, and 11 compounds including 4 OPFRs and 7 BDEs were detected in over 60% of the samples. Children's gender, age, race, recruitment site, and family context were not significantly associated with returning wristbands or compliance with protocols. Comparisons between flame retardant data and socio-demographic information revealed significant differences in total exposures to both ΣBDEs and ΣOPFRs based on age of house, vacuuming frequency, and family context. These results demonstrate that preschool children in Oregon are exposed to BDEs that are no longer being produced in the United States and to OPFRs that have been used as an alternative to polybrominated compounds. Silicone wristbands were well tolerated by young children and were useful for characterizing personal exposure to flame retardants that were not bound to particulate matter.

A Critical Review about the Health Risk Assessment of PAHs and Their Metabolites in Foods

Polycyclic aromatic hydrocarbons (PAHs) are a family of toxicants that are ubiquitous in the environment. These contaminants generate considerable interest, because some of them are highly carcinogenic in laboratory animals and have been implicated in breast, lung, and colon cancers in humans. Dietary intake of PAHs constitutes a major source of exposure in humans. Factors affecting the accumulation of PAHs in the diet, their absorption following ingestion, and strategies to assess risk from exposure to these hydrocarbons following ingestion have received very little attention. This review, therefore, focuses on concentrations of PAHs in widely consumed dietary ingredients along with gastrointestinal absorption rates in humans. Metabolism and bioavailability of PAHs in animal models and the processes, which influence the disposition of these chemicals, are discussed. Finally, based on intake, disposition, and tumorigenesis data, the exposure risk to PAHs from diet is presented. This information is expected to provide a framework for refinements in risk assessment of PAHs.