Determination Of PAHs Research Articles

Determination of PAHs in Surface Sediments along Dakar Coast Using QuECHERS and Gas Chromatography Coupled to Tandem Mass Spectrometry

Determination of PAHs in Surface Sediments along Dakar Coast Using QuECHERS and Gas Chromatography Coupled to Tandem Mass Spectrometry

Effective isolation and comprehensive quantification of EPA16 PAHs, EU15+1 PAHs, 17 halogenated PAHs, and 18 oxygenated PAHs in soybean oil

Halogenated and oxygenated polycyclic aromatic hydrocarbons (XPAHs and OPAHs) have attracted increasing attention due to their considerable or higher toxicity than the corresponding parent PAHs. However, only a few kinds of PAH derivatives were monitored in vegetable oils due to the difficulties in analysis. This study aimed to establish analytical methods for 24 PAHs, 17 XPAHs and 18 OPAHs in soybean oil. The modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) pretreatment followed by GC-MS/MS or UPLC-MS/MS analysis was applied in this study. The results showed that the modified QuEChERS pretreatment could successfully extract 56 PAHs and derivatives in soybean oil, which saved organic solvent to a great extent. Simultaneous determination of EPA16 PAHs, EU15 + 1 PAHs, 17 XPAHs, and 12 OPAHs in soybean oil was achieved by GC-MS/MS analysis, which had recoveries of 61.33–111.61% and relative standard deviations (RSDs) of 1.35–19.89%. UPLC-MS/MS analysis obtained recoveries from 51.61% to 109.45% and RSDs from 1.31% to 15.05% for 14 OPAHs. As a supplement to GC-MS/MS, UPLC-MS/MS exhibited high sensitivity to ortho-OPAHs and benzo[a]pyrene–quinone isomers. Through GC-MS/MS and UPLC-MS/MS analyses, the concentrations of two XPAHs and ten OPAHs in soybean oils were firstly reported. In short, this study offered guidance for comprehensive analyses of PAHs, XPAHs, and OPAHs in vegetable oils.

Controlled construction of 2D hierarchical core-shell ZnO/MnO2 nanosheets on Nitinol fiber with enhanced adsorption performance for selective solid-phase microextraction of trace polycyclic aromatic hydrocarbons in water samples

BackgroundPolycyclic aromatic hydrocarbons (PAHs) are an important class of potentially toxic persistent organic pollutants in environmental water. Their concentrations are usually too low to allow for direct determination with analytical instruments, and the preconcentration is required prior to instrumental analysis. Solid phase microextraction (SPME) is considered as a high-performance green sample preparation technique for volatile and non-volatile organic compounds due to its high enrichment factor. In fact, the nature of SPME coatings governs the adsorption performance. Therefore, more efforts have devoted to the controlled construction of novel long-life SPME fibers with enhanced adsorption performance and improved adsorption selectivity. Results2D hierarchical core-shell ZnO/MnO2 nanosheets (NSs) were constructed on a Nitinol (NiTi) fiber substrate by layer-by-layer assembly for enhanced and selective SPME of PAHs. Firstly, hexagonal ZnO NSs were electrodeposited on the NiTi substrate. Subsequently smaller secondary MnO2 NSs were uniformly grown on the surface of ZnO NSs by a facile hydrothermal oxidation process. ZnO NSs were well protected by the chemically stable MnO2 shell, making the coating highly durable and efficient for SPME application. Meanwhile, the ZnO/MnO2 NSs coating demonstrated superior adsorption performance for PAHs. After the optimization of SPME conditions, the proposed SPME-HPLC-UV method exhibited good analytical performance for preconcentrating and determining trace PAHs with wide linear ranges (0.03–200 μg L−1) and low LODs (0.005–0.112 μg L−1) as well as good repeatability (1.4%-6.9%) and fiber-to-fiber reproducibility (5.3%-7.1%). Moreover, the proposed method showed good precision and recovery in the preconcentration and determination of target PAHs in real water samples. SignificanceAs compared with representative commercially available fibers, the NiTi@ZnO/MnO2 NSs fiber showed enhanced adsorption efficiency and improved adsorption selectivity for PAHs. The constructed fiber can be used as an alternative to commercial fibers for the adsorption and preconcentration of target PAHs in the environmental water samples. Moreover, the preparation strategy is expected to provide new insights into the precisely controlled construction of the efficient and stable core-shell bimetallic oxide nanostructures on the superielastic NiTi-based fibers.

Chemical and microbiological insights into two littoral Antarctic demosponge species: Haliclona (Rhizoniera) dancoi (Topsent 1901) and Haliclona (Rhizoniera) scotti (Kirkpatrick 1907).

Antarctic Porifera have gained increasing interest as hosts of diversified associated microbial communities that could provide interesting insights on the holobiome system and its relation with environmental parameters. The Antarctic demosponge species Haliclona dancoi and Haliclona scotti were targeted for the determination of persistent organic pollutant (i. e., polychlorobiphenyls, PCBs, and polycyclic aromatic hydrocarbons, PAHs) and trace metal concentrations, along with the characterization of the associated prokaryotic communities by the 16S rRNA next generation sequencing, to evaluate possible relationships between pollutant accumulation (e.g., as a stress factor) and prokaryotic community composition in Antarctic sponges. To the best of our knowledge, this approach has been never applied before. Notably, both chemical and microbiological data on H. scotti (a quite rare species in the Ross Sea) are here reported for the first time, as well as the determination of PAHs in Antarctic Porifera. Both sponge species generally contained higher amounts of pollutants than the surrounding sediment and seawater, thus demonstrating their accumulation capability. The structure of the associated prokaryotic communities, even if differing at order and genus levels between the two sponge species, was dominated by Proteobacteria and Bacteroidota (with Archaea abundances that were negligible) and appeared in sharp contrast to communities inhabiting the bulk environment. Results suggested that some bacterial groups associated with H. dancoi and H. scotti were significantly (positively or negatively) correlated to the occurrence of certain contaminants.

Rapid and sensitive method for the simultaneous determination of PAHs and alkyl-PAHs in scrubber water using HS-SPME-GC–MS/MS

Scrubber water, a waste stream generated by ships exhaust gas cleaning systems, may pose a threat when released into the marine environment due to potential contamination with polycyclic aromatic hydrocarbons (PAHs) and their alkyl derivatives (alkyl-PAHs). This study aims to develop a reliable analytical procedure combining headspace solid-phase microextraction (HS-SPME) with gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC–MS/MS) to simultaneously separate and determine target compounds in aqueous samples. Method validation demonstrated good linearity up to 200 ng L−1 (r2> 0.996) and low limits of detection (0.33 to 1.67 ng L−1, except for naphthalene at 3.3 ng L−1). The method shows good precision (RSD<20%) and satisfactory analytical recoveries. The methodology was successfully applied to scrubber water samples collected from a container ship and the results highlight the prevalence of naphthalene, phenanthrene, and their alkyl derivatives.•Rapid and reproducible HS-SPME-GC–MS/MS method for the analysis of PAHs and alkyl-PAHs in scrubber water.•The capacity of SPME to analyze both filtered and unfiltered samples was assessed, showing that the more hydrophobic PAHs may be lost during filtration.

Composition, Concentration and Origin of Polycyclic Aromatic Hydrocarbons in Waters and Bottom Sediments of Lake Baikal and Its Tributaries

The aim of this study was the systematization and generalization of data obtained by authors during the last decade and the comparison of these data with those obtained by other authors. Gas chromatography (GC-MS) was used for the determination of PAHs and the positive matrix factorization (PMF) model and principal component analysis (PCA) were used for source apportionment of PAHs. It was found that the total concentration of 16 priority PAHs in surface waters varied from 5 to 200 ng/L, whereas the concentration of 16 PAHs in bottom sediments varied from 50 to 700 ng/g. The 2–3-ring PAHs were dominant in water, whereas the 4–6-ring PAHs were dominant in sediments. That was due to PAHs fractionation in the soil–water system. The source apportionment results showed that the PAHs in both water and sediments mostly originated from the combustion of biomass and fossil fuels. In contrast to sediments, there was a PAH fraction in water that did not originate from a single source. The pollution of freshwater ecosystems manifested itself in the lack of correlation between values of octanol/water partitioning coefficients and sediment/water partitioning coefficients of PAHs.

A novel multiwalled carbon nanotube–cyclodextrin nanocomposite for solid-phase microextraction–gas chromatography–mass spectrometry determination of polycyclic aromatic hydrocarbons in snow samples

Novel solid-phase microextractioncoatings based on the use of multiwalled carbon nanotube–cyclodextrin (MWCNT-CD) nanocomposites were developed for the determination of 16-priority polycyclic aromatic hydrocarbons at ultratrace levels in snow samples. The performance of both β- and γ-CD was tested to increase the detection capabilities towards the heaviest and most lipophilic compounds, i.e., five- and six-ring PAHs. To facilitate the interactions of MWCNTs with CDs, an oxidation procedure using both HNO3 and H2O2 was applied, obtaining superior results using MWCNTs-H2O2-γ-CD fiber. Detection and quantitation limits below 0.7 and 2.3 ng/L, RSD lower than 21%, and recoveries of 88(± 2)–119.8(± 0.4)% proved the reliability of the developed method for the determination of PAHs at ultratrace levels. The complexation capability of the γ-CD was also demonstrated in solution by NMR and fluorescence spectroscopy studies and at solid state by XRD analysis. Finally, snow samples collected in the ski area of Dolomiti di Brenta were analyzed, showing a different distribution of the 16 priority PAHs, being naphthalene, phenanthrene, fluoranthene, and pyrene the only compounds detected in all the analyzed samples.Graphical

DETERMINATION OF CONDENSABLE PARTICULATE MATTER RELEASED BY THE COMBUSTION OF SOLID FUELS IN LOW-POWER BOILERS

Despite significant emission control steps in recent decades, damage to air quality caused byparticulate matter with a diameter of 2.5 m or less is now a major concern on a global scale.Condensable particulate matters (CPM) due to their significant contribution to the totalconcentration of particulate matter and their small aerodynamic size (below 2.5 m) are now ofwidespread interest. CPMs produced in low-power solid fuel heating systems can be one of themain components of the total mass of fine particles present in the air we breathe. The operatingconditions of large power installations and small heating boilers differ significantly, therefore itis necessary to adapt the research methods adapted to industrial installations, to the low-powerboilers. In the tests, three fuels were combusted in two low-power boilers (18 kW boiler witha suction feeder and 5class 14 kW boiler with a screw feeder): bituminous coal, pine and sprucewood pellets and cereal straw pellets. An EPA 202 method was used to collect the CPM. Qualitativeand quantitative analyses of inorganic and organic CPM components were performed. Analysesof the inorganic part of the CPM included the determination of metals m.in Na, Ca, Fe, Mg, Al,K, and water-soluble ions, m.in SO42, Na+, K+ and Cl, while analyses of the organic part of theCPM comprised the determination of PAHs. Differences were observed in the amount of CPMgenerated depending on the fuel used and the type of low-power boiler used. CPM emissions arerelatively high and constitute a large part of total particulate matter, so the impact of CPM on theenvironment cannot be ignored and we should pay special attention to its research and control,especially from small solid fuel heating boilers.

Determination of PAHs, PAH-Derivatives and Other Concerning Substances in Posidonia oceanica Seagrass and Marine Sediments by High Resolution Mass Spectrometry

The Posidonia oceanica decline due to climate change and other anthropogenic pressures, such as chemical pollution, is well known in the scientific community. However, a comprehensive study of the full content of the organic micropollutants found in this significant seagrass has not yet been carried out. Second, an eco-friendly extraction procedure that does not require a large sample, preserves the seagrass’s ecological integrity and functions, and follows green-chemistry principles, is lacking. These information gaps represent the aims of this study. For this purpose, trials with diverse simple and affordable extraction methods to detect one of the most ubiquitous contaminants (polycyclic aromatic hydrocarbons or PAHs) were conducted. As a result, the use and validation of a polytron homogenizer and an ultrasonic bath were proposed for the extraction of priority PAHs from tissues of P. oceanica and marine sediments, respectively. Tissues (leaves and rhizomes) of P. oceanica and sediment samples were collected, extracted, and subjected to a thorough analysis, i.e., target, suspect, and unknown screenings, using gas chromatography coupled to high resolution mass spectrometry (GC-Q-Orbitrap MS). Target analysis revealed seven priority parent-PAHs, whilst during the suspect screening, four PAH-derivatives and three other parent-PAHs were tentatively identified. In the additional third unknown analysis, 11 structures, several with concerning toxicity, were also tentatively identified. Numerous of the identified compounds showed elevated detection frequency in the environmental samples, even reaching 100%, such as the cases of the parent-PAHs (naphthalene, phenanthrene and retene), some PAH-derivatives, one UV stabilizer, and plastic additives along with pesticides. The methods proposed here should be considered for future monitoring of P. oceanica, as well as the three-way analytic approach (target, suspect and unknown), to obtain a more real and accurate idea of the organic micropollutants content in the environment.

Development and validation of a new method for the simultaneous determination of PAHs and NDL-PCBs in fish by GC-SQ-MS.

A new method for the simultaneous determination of PAHs and NDL-PCBs in fish and fish products was developed and validated using a GC-SQ-MS system. The efficacy of different solvents for a quantitative extraction was studied, as was the efficacy of different sorbents for sample clean up. The developed method, which includes extraction by DCM and sample clean up by SPE using Isolute® SI cartridges, was statistically validated at two concentration levels by assessing: accuracy, precision, limit of quantification, limit of detection and matrix effect. The method was used for analysing fresh, frozen and smoked fish products from the Greek retail market. None of the samples examined showed results above the maximum limits set by EU regulations.

Optimization of QuEChERS and high performance liquid chromatography-fluorescence detection conditions to assess the impact of preparation procedures on EU priority PAHs in coffee samples and their PAHs consumption risk.

The good performance conditions for determination of EU priority PAHs in coffee samples were established to evaluate the effects of roasting degree on the PAHs in coffee beans and the brewing methods on the PAHs transfer from coffee beans to their brews. The consumption risk of the PAHs in coffee products was also assessed. The PAHs levels of the roasted coffee beans were in the order: 923.65 ng/g (dark roast) > 132.20 ng/g (medium roast) > 69.28 ng/g (light roast). Compared with general brewing with the drip bag (PAHs content, 0.30-0.62 ng/mL in coffee brews), the coffee machine brewing (set at 4 bar) induced higher PAHs release into coffee brews (PAHs content, 0.36-2.14 ng/g). The PAHs amounts of the commercial brewed and canned coffee products were 0.32-1.23 ng/g and 0.16-0.46 ng/g, respectively. The consumption risk of the PAHs in the coffee brews and products is a low level of concern.

STUDY OF SKIN CHANGES, HAND ABNORMALITIES AND PULMONARY MANIFESTATIONS IN DIFFUSE SCLERODERMA IN A TERTIARY CARE HOSPITAL OF EASTERN INDIA

Introduction: Scleroderma is a connective tissue disease characterized by brosis affecting the skin and internal organs.Joint involvement has been reported to occur in 46%- 97% of SSc patients. Bone and soft tissues may also be targeted; calcinosis and acro-osteolysis are thought to be the main characteristic ndings in SSc. Pulmonary disease in SSc falls into two major categories: interstitial lung disease (ILD) and pulmonary hypertension. Using PFTs, signicant pulmonary involvement is detectable in 25% of the patients with SSc within 3 years of initial diagnosis. The gold standard for determination of PAH in patients with SSc is right heart catheterization. The HRCT features of lung disease are ground-glass opacication predominant or admixed with reticular abnormalities in the majority of cases and little or no honeycombing. To study the demographic prole, Clini Aims and Objectives: cal Manifestations, Radiological abnormalities, Lung involvement and PAH. 35 newly diagnosed Sclederma patients Materials and Methods: attending Medicine and Rheumatology OPD of Medical College Kolkata were studied in this Cross-sectional observational study. Clinical Manifestations are noted and Radiological Investigations were recorded in structured Proforma. Data analysed using standard statistical methods. In Results and Analysis: our study, the study population had an F: M ratio of 10:1. majority of population (38%) having age group(30-40) yrs followed by less than 30 yrs &amp; 41yrs or more (31% each). In our study clinically hand abnormality was evident in 69% patients &amp; radiologically hand abnormality was evident in 74% patients. In our study population 29% patients have had acroosteolysis, 26% patients had erosion &amp; 19% patients had exion contracture. In our study we found all the patient with documented ILD had abnormal PFT. In our study group restrictive pattern in PFT was evident in 63% patients &amp; mixed pattern was evident in 23% patients. Twelve patients (35% of the total cohort) had pulmonary hypertension dened as PAs of 30 mm Hg or greater. In our study we found Out of 30 patients with documented ILD in HRCT 20 patients had PAH &amp; 10 patients had no PAH. Females are more affected than males. Majority Conclusion: of the patients affected are in the age group of 30-40 years.69% patients had clinically evident hand abnormality and 74% patients had radiologically evident hand abnormality.CXR showed ILD in 63% patients whereas86% patients had documented ILD in HRCT.Restrictive pattern of PFT abnormality is more than mixed pattern.57% patients had documented PAH in echocardiography.HRCT is more sensitive than chest radiography for detection of ILD.

HAP-TiO2 nanocomposites based electrochemical sensor for selective and simultaneous detection of para-aminohippuric acid and uric acid

Kidney diagnosis by p-aminohippuric acid (PAH) test indicates the ability of the kidney to combine benzoic acid with PAH by determination of the latter eliminated in urine or blood serum. Hippuric acid synthesis also occurs in both the liver and cortical cells of the kidney. However, the PAH test did not become popular because of the non-availability of a simple method for quick and accurate determination of the PAH at an affordable cost. Here, we report a novel electrochemical sensor based on hydroxyapatite-titanium dioxide (HAP-TiO2) nanocomposite for quantifying specific biomarkers PAH and uric acid (UA). Nanostructured HAP and TiO2 powders have been synthesized independently by microwave irradiation and hydrolysis methods respectively and the composites are prepared by mixing the appropriate amounts of HAP and TiO2 under sonication. Voltammetric studies of HAP-TiO2 modified glassy carbon electrodes exhibited improved electrocatalytic activity towards the oxidation of PAH and UA in a phosphate buffer saline (pH7.0). Under the optimized conditions, the oxidation peak currents are linearly proportional to PAH and UA concentrations over wide linear ranges of 50 nM to 5.760 mM, and the corresponding lowest detection limits are estimated to be 37 nM and 43 nM (S/N = 3). The fabricated electrode has been successfully implemented for the determination of PAH and UA in human urine samples. Performance of the device in terms of sensitivity, specificity, and linear range fulfills the requirement for screening the chosen biomarkers simultaneously making it suitable for clinical non-invasive liver and kidney diagnoses.

Polycyclic aromatic hydrocarbons and trace elements dietary intake in inhabitants of Athens, Greece, based on a duplicate portion study

Concentration levels of 26 polycyclic aromatic hydrocarbons and 20 trace elements were measured in dietary samples, in order to estimate the dietary intake and the potential exposure risk of the Greek population. Dietary samples were collected with the help of 30 volunteers inhabitants of Athens, Greece, according to the duplicate portion study (DPS) method where the determination of the compounds is conducted in the final consumed meal. DPS was selected as an alternative to a total diet study for its feasibility, low cost and realistic image that it provides. PAHs determination was performed by gas chromatography tandem mass spectrometry (GC-MS/MS) and trace elements determination by inductively coupled plasma mass spectrometry (ICP-MS). The estimated mean daily dietary exposure on 26 PAHs for an adult was estimated at 101.47 ng kg−1 body weight day−1, while moderate to low exposure was related to the type and amount of food consumed. Exposure levels to PAHs do not indicate a possible risk for the health of the study group. For toxic, potentially essential and/or essential trace elements the daily exposure calculated for Greek population was in accordance with the reference values of the health-based guidances and compared to previous diet studies reported for the population of other countries was in general similar to the lower bound exposure.

Hydrothermal in situ growth and application of a novel flower-like phosphorous-doped titanium oxide nanoflakes on titanium alloy substrate for enhanced solid-phase microextraction of polycyclic aromatic hydrocarbons in water samples

A novel flower-like phosphorous-doped titanium oxide nanocomposite coating was in situ grown on nickel-titanium alloy (NiTi) fiber by hydrothermal treatment in phosphoric acid solution. The experimental results demonstrated that phosphorous-doped titanium oxide nanoflakes (P-TiONFs) with an average thickness of 80 nm were formed on the NiTi fiber substrate in 0.1 mol L−1 H3PO4 at 150 °C for 6 h. Thereafter, the resulting P-TiONFs were used as SPME fiber coatings for the adsorption of typical aromatic analytes from environmental water samples, which were determined by HPLC-UV. These P-TiONFs exhibited good adsorption selectivity for hydrophobic PAHs. After optimizing microextraction conditions, linear responses were achieved in the ranges of 0.05–200 μg L−1 for the determination of PAHs with determination coefficients higher than 0.999. LODs (S/N = 3) ranged from 0.009 to 0.132 μg L−1, while LOQs (S/N = 10) ranged from 0.030 to 0.441 μg L−1. RSDs for intra-day and inter-day analyses with a single fiber varied from 4.46% to 5.56% and 5.14%–6.75%, respectively. The relative recoveries of 83.60%–119.0% were achieved for the determination of PAHs in real water samples spiked at the concentration levels of 5.0 μg L−1 and 10.0 μg L−1 with RSDs below 7.38%. In addition, the fibers exhibited no significant decrease in adsorption efficiency after being used 240 adsorption and desorption cycles. The proposed method was successfully applied to the selective enrichment and determination of target PAHs in different water samples.

Efficient solid phase microextraction of organic pollutants based on graphene oxide/chitosan aerogel

The design and synthesis of novel high-performance solid phase microextraction (SPME) coatings towards organic pollutants with diverse chemical properties is still a challenge in sample preparation. Herein, a stable chitosan cross-linked graphene oxide (GOCS) aerogel was reported as a novel coating for solid phase microextraction. The interpenetrated meso- and macropores ensured the large surface area and high accessibility of the functional groups across the aerogel, resulting in high extraction performance towards target hydrophobic pollutants. The extraction capacities of the GOCS-coated SPME fiber towards analytes (e.g. polycyclic aromatic hydrocarbons, organophosphorus pesticides, organochlorine pesticides, pyrethroids, and polychlorinated biphenyls) were about 0.5–13 times as high as those obtained by the commercial fibers (30 μm polydimethylsiloxane (PDMS), 65 μm polydimethylsiloxane/divinylbenzene (PDMS/DVB)), which was attributed to the hydrophobic, π-π, halogen bond and hydrogen bond interactions between the coating and the analytes. Under the optimized extraction conditions, superior analytical performances for PAHs were achieved with a wide linearity (0.5–1000 ng L−1), high enhancement factors (311–3740), and the low limits of detection (0.03–1.28 ng L−1). Finally, the GOCS-coated SPME fiber was successfully applied to the determination of PAHs in real water samples with good recoveries (91.6%–110%).

Development of a novel porous cobalt, phosphorus and nitrogen co-doped carbonaceous coating by phosphiding ZIF-67 grown on nitinol fiber for selective solid-phase microextraction of polycyclic aromatic hydrocarbons from water samples.

The nature and fabrication of the fiber coatings with good adsorption capacity and selectivity play a decisive role in solid-phase microextraction (SPME). In this work, a facile strategy was proposed to fabricate a cobalt, phosphorus and nitrogen co-doped carbonaceous (Co-P-NC) coating on superelastic nitinol (NiTi) substrate as a binder-free fiber for SPME. In particular, direct electrochemical in situ growth of ZIF-67 crystals served as the N-containing carbon precursor and sacrificial template for subsequent controllable conversion of ZIF-67 into a novel porous Co-P-NC coating on the NiTi wire substrate via a phosphiding process in a N2 atmosphere. The obtained NiTi wire with the Co-P-NC coating (NiTi@Co-P-NC) was employed to investigate the adsorption of some representative aromatic analytes in water samples for the first time coupling with high-performance liquid chromatography with UV detection (HPLC/UV). The results proved that the resulting fiber showed superior adsorption selectivity for polycyclic aromatic hydrocarbons (PAHs). Therefore, the key parameters were further examined for the adsorption and preconcentration of PAHs. Under the obtained conditions, linear chromatographic responses were achieved over the concentration ranges of 0.03-100 μg L-1 with the correlation coefficients ranging from 0.9980 to 0.9991. Limits of detection (LODs) were between 0.007 and 0.149 μg L-1 (S/N = 3). The developed SPME-HPLC/UV method was applied to selective preconcentration and sensitive determination of PAHs in water. Moreover, this fiber had good fiber preparation reproducibility and presented 120 adsorption and desorption cycles at the same time in practical SPME application.

Comparison of Polycyclic Aromatic Hydrocarbons, Pahs Concentration Levels in Types of Beans and Maize from Markets in South East Nigeria

Polycyclic aromatic hydrocarbons, PAHs are carcinogenic, mutagenic and persistent organic compounds commonly generated from incomplete combustion of organic matters. Beans,<i> Phaseolus vulgaris</i> and maize,<i> Zea mays</i> form part of staple foods commonly consumed and are highly rich in protein and carbohydrate respectively. This study compared the concentration levels of the sixteen priority PAHs in different types of beans (Potasikum, white iron, brown iron, Gausau and Nija red) and maize (white, yellow and pop corn) obtained from various markets in south east Nigeria. The purchased beans and maize samples were picked, ground and extraction was by sonication with a solvent mixture of dichloromethane and hexane in the ratio of 3:1. The determination of PAHs was by gas chromatography coupled with flame ionization detector, GC-FID. The result showed that the PAHs concentration levels (× 10^-2 µg/kg) of lower molecular weight PAHs, LMW detected in the analyzed beans samples ranged from 8.842±4.743 to 12.590±8.068 in white iron beans and brown iron beans respectively with percentages of 41.09% and 44.90% and 5.998±4.725 to 9.385±11.339 in pop and white corn respectively at 25.58% and 34.46%. While the high molecular weight, HMW PAHs concentration levels (× 10^-2 µg/kg) varied from 12.673±5.554 in white iron beans to 16.998±3.129 in Nija red beans at 58.88% and 63.95% and from 17.84±11.768 in pop maize to 18.153±10.421 in yellow maize at 74.83% and 67.43% respectively. The probable carcinogenic PAH8 concentrations detected varied from (8.875±2.725 to 11.796±3.018) × 10^-2 µg/kg in white iron beans and brown iron beans respectively and from (10.82±6.183 to 13.573±8.789) × 10^-2 µg/kg in pop and yellow maize respectively.. Diagnostic ratio calculated showed fuel combustion to be the main source of emission. The sixteen priority PAHs were detected in all the analyzed samples at a very low concentration levels, lower than the permissible limit of 1.0 µg/kg established by EFSA for cereals and cereal based products. Hence these (PAHs) can at a long time accumulation in the body be very harmful. There is need to establish a permissible limit of PAHs in beans and other legume grains by either European Food Safety Authority, EFSA or other regulatory bodies.

Controllable growth of flower-like hierarchical CoNiO2 nanoflakes anchored on Nitinol fiber substrate with good selectivity for highly efficient solid-phase microextraction of polycyclic aromatic hydrocarbons in water

The flower-like hierarchical cobalt nickel oxide nanoflakes (CoNiO2NFs) with a porous structure were fabricated on Nitinol (NiTi) fiber substrate by a hydrothermal reaction and subsequent annealing treatment. The morphology affected by the molar ratios of Ni to Co and counter ions in starting precursors as well as hydrothermal reaction temperature and time was investigated in detail. The obtained CoNiO2NFs coating exhibited outstanding performance for the selective extraction of PAHs. After optimizing the main parameters that affected extraction through orthogonal experiments, the developed method showed good linearity in the ranges of 0.05 μg L−1 - 200 μg L−1 with the determination coefficient >0.999. LODs were between 0.006 μg L−1 and 0.114 μg L−1, LOQs were in the ranges of 0.020–0.376 μg L−1 and RSDs were below 5.19% and 5.71% for intra-day and inter-day analyses, respectively. The developed method was successfully applied to selective enrichment and determination of target PAHs in real water samples. Moreover, the fabricated fiber exhibited high chemical and mechanical stability, and could withstand more than 260 extraction-desorption cycles without loss of its extraction efficiency.

Rapid and Highly Efficient Solid-Phase Microextraction Based on in Situ Derivation of Robust Carbonaceous Nanostrips on Anodized Titanium Fiber for Sensitive Determination of Polycyclic Aromatic Hydrocarbons in Environmental Water

With titanium wire as a titanium source and a fiber substrate, titania nanostrips (TiO2NSs) were in situ grown on the fiber surface by electrochemical anodization and used as supporting templates for subsequent uniform deposition of polar glucose via hydrothermal reaction. After annealing, controllable in situ derivation of TiO2NSs-templated carbonaceous coating (TiO2@CNSs) was achieved on the Ti fiber substrate. Coupled to high-performance liquid chromatography with UV detection, the extraction performance was investigated using representative aromatic compounds as model analytes and compared with those of commercially available fibers. The results demonstrated that the Ti@TiO2@CNSs fiber exhibited good extraction selectivity for PAHs, especially for high-molecular-weight PAHs. For this purpose, the key parameters affecting extraction efficiency of PAHs were optimized. Under optimized conditions, linearity was shown in the ranges of 0.02–200 μg·L−1 with the correlation coefficients of greater than 0.999. Limits of detection were 0.005–0.056 μg·L−1. The intra-day and inter-day repeatability of the proposed method with the single fiber varied from 2.06% to 3.99% and from 2.85% to 5.17%, respectively. The fiber-to-fiber reproducibility ranged from 2.86% to 5.21%. The proposed method was successfully applied to selective preconcentration and sensitive determination of target PAHs in real water samples. Moreover, this fiber has a long service time.