Polycyclic Aromatic Hydrocarbons In Solution Research Articles

An ultrasound assisted dispersive micro solid-phase extraction and a composite ionic liquid-metal organic framework for sixteen polycyclic aromatic hydrocarbons analysis in fruit juice and environmental water samples

Aluminum-based metal organic framework composite containing ionic liquid was prepared and used as sorbent for extraction of sixteen polycyclic aromatic hydrocarbons in list of priority pollutants of United States Environmental Protection Agency before their analysis by gas chromatography/mass spectrometry. The dispersive micro solid-phase extraction method, known as a simple and fast method, was preferred as the extraction method. The optimized parameter conditions were 5 mL of sample solution, 10 min sonication by ultrasonic bath, 30 mg of sorbent, 30 °C extraction temperature, 0.1 mL of hexane as elution solvent with 5 min elution time. The suggested method presented that limit of detection and limit of quantification were in the range of 0.01–0.10 μg l-1, and 0.04–0.33 μg L-1, respectively. The intra-day and inter-day repeatability were within the ranges of 1.18–4.88 % and 1.02–5.06 %, respectively. The recoveries for polycyclic aromatic hydrocarbons in peach juice, cherry juice, tap water and rain water samples were obtained in the range of 84.9–99.9 % for spiked 5, 50 and 100 μg l-1 standard polycyclic aromatic hydrocarbons solution.

Characteristics of polycyclic aromatic hydrocarbons (PAHs) removal by nanofiltration with and without coexisting organics

Polycyclic aromatic hydrocarbons (PAHs) are contaminants of great concern owing to their persistence, toxicity, and bioaccumulation in aquatic environments. In this study, nanofiltration (NF) was used to investigate the removal of naphthalene (NAP) and phenanthrene (PHE) using three membranes of NF270, NF90, and DK. Subsequently, we examined the effects of coexisting organics on PAHs removal. Based on the results, DK was determined to be the optimal membrane for removing PAHs by comparing the membrane flux and pollutant rejection. The membrane flux reached 34.32 L/m2·h, and the NAP and PHE rejections were 92.21% and 97.85%, respectively, at transmembrane pressure (TMP) of 5 bar using DK. Coexisting organics decreased the membrane fluxes of NF270 and DK in the following order: protein > glucose > humic acid. The NAP and PHE rejections were obviously improved using NF270 in the following order: humic acid > protein > glucose. The PHE rejection was slightly improved using DK. A low concentration of organics could reduce the NAP rejection using DK; however, the NAP rejection could be restored at high concentrations of organics, except for humic acid. Coexisting organics could cause severe membrane fouling. The order of the effect of different coexisting organics on membrane fouling was protein > humic acid > glucose. The total investment and operating costs were about 1.47 and 0.187 million dollars, respectively, for treating PAHs solution using DK when the feed flow was 300 m3/d.

Kinetic study on the adsorption of some polycyclic aromatic hydrocarbons using dinitrodiphenyldiquinoline adsorbent

In this study, a dinitrodiphenyldiquinoline derivative is synthesized, purified, and characterized, and its adsorptive ability is examined for the first time. Twelve common polycyclic aromatic hydrocarbons are chosen as potential adsorbates for removal by using dinitrodiphenyldiquinoline as an adsorbent surface. The adsorptive capacity and the efficiency of removal depend on several variables such as adsorbent dose, polycyclic aromatic hydrocarbon initial concentration, pH, and contact time. This paper summarizes the adsorbent parameters and the kinetic models that can optimize and describe the adsorption process used to treat aqueous solutions of polycyclic aromatic hydrocarbons. Experimentally, the optimum adsorbent dose, the initial concentration, and contact time are found to be 0.1 g, 1 ppm, and 60 min, respectively. Mathematical treatment of the adsorption data reveals that the adsorption of all the polycyclic aromatic hydrocarbons by dinitrodiphenyldiquinoline adopted a pseudo second-order adsorption model. As a result, the dinitrodiphenyldiquinoline derivative is found to be a very good adsorbent surface for several hazardous organic pollutants such as polycyclic aromatic hydrocarbons.

Synthesis of isocoumarins and PAHs with electron-withdrawing substituents: Impact of the substituent nature on the photophysical behavior

The efficient conditions for rhodium catalyzed oxidative coupling of electron-poor carboxylic acids with diphenylacetylene have been optimized. The best protocol uses Ag2CO3 as an oxidant and DMF as a solvent. The reactions smoothly proceed with the formation of isocoumarins and polycyclic aromatic hydrocarbons (PAHs). The isonicotinic, coumalic, coumarin-3-carboxylic, 4-nitrobenzoic, 4-cyanobenzoic, 4-(ethoxycarbonyl)benzoic, and terephthalic acids were successfully involved in the annulation. In contrast, in the case of picolinic acid, the formation of the stable chelate complex Cp*RhCl(O,N-pic) prohibits the catalytic reaction. The photophysical properties of isocoumarins and PAHs in solutions, such as fluorescence emission and solvatochromic effects, have been studied. In particular, the isocoumarin dyes demonstrate a phenomenon of aggregation-induced emission, while PAHs with electron-withdrawing substituents exhibit strong fluorescence emission in the violet region (370–390 nm) with quantum yields up to 55%.

MoS2 Defect Healing for High-Performance Chemical Sensing of Polycyclic Aromatic Hydrocarbons.

The increasing population and industrial development are responsible for environmental pollution. Among toxic chemicals, polycyclic aromatic hydrocarbons (PAHs) are highly carcinogenic contaminants resulting from the incomplete combustion of organic materials. Two-dimensional materials, such as transition metal dichalcogenides (TMDCs), are ideal sensory scaffolds, combining high surface-to-volume ratio with physical and chemical properties that are strongly susceptible to environmental changes. TMDCs can be integrated in field-effect transistors (FETs), which can operate as high-performance chemical detectors of (non)covalent interaction with small molecules. Here, we have developed MoS2-based FETs as platforms for PAHs sensing, relying on the affinity of the planar polyaromatic molecules for the basal plane of MoS2 and the structural defects in its lattice. X-ray photoelectron spectroscopy analysis, photoluminescence measurements, and transfer characteristics showed a notable reduction in the defectiveness of MoS2 and a p-type doping upon exposure to PAHs solutions, with a magnitude determined by the correlation between the ionization energies (EI) of the PAH and that of MoS2. Naphthalene, endowed with the higher EI among the studied PAHs, exhibited the highest output. We observed a log-log correlation between MoS2 doping and naphthalene concentration in water in a wide range (10-9-10-6 M), as well as a reversible response to the analyte. Naphthalene concentrations as low as 0.128 ppb were detected, being below the limits imposed by health regulations for drinking water. Furthermore, our MoS2 devices can reversibly detect vapors of naphthalene with both an electrical and optical readout, confirming that our architecture could operate as a dual sensing platform.

First isolation of biodegradable polycyclic aromatic hydrocarbons Mycobacterium porcinum and Mycobacterium celeriflavum from oil-polluted ecosystems

Background: Polycyclic aromatic hydrocarbons (PAHs) have detrimental effects on human, ecosystem, and biodiversity. Bioremediation is an option that has been used to remediate and reduce the risk of contaminants such as PAHs. Microorganisms are readily available to screen and can be rapidly identified to be used in many extreme environmental conditions. Mycobacteria have a great potential for the production of bioactive compound, which have degradation activity. Due to this issue, and also, as there is no study conducted on the biodiversity of biodegradable Mycobacterium in Markazi province, the present study aimed to assess the isolation and identification of biodegradable Mycobacterium species from diverse Markazi province ecosystems. Methods: Mycobacterium were screened from a total of 30 soil, water, and sludge samples from the oil-polluted ecosystems of Markazi province and characterized to the genus and species level by applying molecular and conventional microbiological assay including the PCR amplification and sequence analysis of 16SrRNA and hsp65 genes. The growth rate in the presence of PAHs, turbidometry, and high performance liquid chromatography (HPLC) were used to determine their bioremediation capability. Results: In total, 6 Mycobacterium isolates (20%) were screened from 30 samples, which belonged to two species of Mycobacterium consisting of M. porcinum (4 isolates) and M. celeriflavum (2 isolates). The strains of M. porcinum and M. celeriflavum could degrade 70% and 90% of 1 mg/L PAH solution in 7 days. Conclusion: According to the results, the M. porcinum and M. celeriflavum have a significant capability to biodegrade the PAHs. Therefore, more investigations are recommended for separation and applicational use of the mycobacterium species for bioremediation of PAHs.

Pyromellitic Diimide-Extended Pillar[6]arene: Synthesis, Structure, and Its Complexation with Polycyclic Aromatic Hydrocarbons.

A novel pyromellitic diimide-extended pillar[6]arene was synthesized in two steps with moderate yield for the first time. It showed a symmetrical stretched hexagon structure and could form 1:2 complexes with polycyclic aromatic hydrocarbons in solution. Interestingly, a linear supramolecular array between complex 1@G42 and pyrene through π···π stacking interactions was also observed in the solid state.

Treatment of polycyclic aromatic hydrocarbons (PAHs) from aqueous solutions by flotation using colloidal gas aphrons

Aqueous solutions contaminated with polycyclic aromatic hydrocarbons (PAHs) pose severe environmental risks, making their removal necessary. Flotation with colloidal gas aphrons (CGAs) has recently demonstrated high removal efficiencies for various pollutants present in aqueous solutions. This study determined the efficacy of CGAs in removing low-ring PAHs (naphthalene, fluorene, and phenanthrene) from aqueous solutions. CGAs were produced from different surfactants, such as anionic sodium dodecylbenzene sulfonate (SDBS), cationic hexadecyl trimethylammonium bromide (HTAB), and natural surfactant obtained from the leaves of Ziziphus spina-christi (ZSC). PAHs removal efficiency was studied by varying different parameters, such as type of surfactant, PAHs solution pH, CGAs flow rate, and PAHs and CGAs solution temperature. Results showed that at pH 5.6 and 25 °C, fluorene and phenanthrene were fully removed using CGAs (flow rate of 100 mL/min) derived from cationic HTAB surfactant, while naphthalene was removed to the extent of approximately 88.4% under similar conditions. These findings suggest that CGAs derived from cationic HTAB surfactant have a greater capacity for extracting low-ring PAHs from aqueous media.

Evaluation of an Ozone Chamber as a Routine Method to Decontaminate Firefighters' PPE.

Ozone chambers have emerged as an alternative method to decontaminate firefighters’ Personal Protective Equipment (PPE) from toxic fire residues. This work evaluated the efficiency of using an ozone chamber to clean firefighters’ PPE. This was achieved by studying the degradation of pyrene and 9-methylanthracene polycyclic aromatic hydrocarbons (PAHs). The following experiments were performed: (i) insufflating ozone into PAH solutions (homogeneous setup), and (ii) exposing pieces of PPE impregnated with the PAHs to an ozone atmosphere for up to one hour (heterogeneous setup). The ozonolysis products were assessed by Fourier Transform Infrared Spectroscopy (FTIR), Thin-Layer Chromatography (TLC), and Mass Spectrometry (MS) analysis. In the homogeneous experiments, compounds of a higher molecular weight were produced due to the incorporation of oxygen into the PAH structures. Some of these new compounds included 4-oxapyren-5-one (m/z 220) and phenanthrene-4,5-dicarboxaldehyde (m/z 234) from pyrene; or 9-anthracenecarboxaldehyde (m/z 207) and hydroxy-9,10-anthracenedione (m/z 225) from 9-methylanthracene. In the heterogeneous experiments, a lower oxidation was revealed, since no byproducts were detected using FTIR and TLC, but only using MS. However, in both experiments, significant amounts of the original PAHs were still present even after one hour of ozone treatment. Thus, although some partial chemical degradation was observed, the remaining PAH and the new oxygenated-PAH compounds (equally or more toxic than the initial molecules) alerted us of the risks to firefighters’ health when using an ozone chamber as a unique decontamination method. These results do not prove the ozone-advertised efficiency of the ozone chambers for decontaminating (degrading the toxic combustion residues into innocuous compounds) firefighters’ PPE.

Negative Consequences on the Growth, Morphometry, and Community Structure of the Kelp Macrocystis pyrifera (Phaeophyceae, Ochrophyta) by a Short Pollution Pulse of Heavy Metals and PAHs.

The study of pollution effects in the marine environment has become important in recent decades, and the exposure to simultaneous pollutants has become especially relevant. Indeed, the study of key organisms, such as ecosystem engineers, can show a broader view of the effects of pollutants. In this context, we evaluate in situ the effects of a short (7-day) pollution pulse of combined solutions of heavy metals and polycyclic aromatic hydrocarbons (PAHs) (Cu + PAHs, Cd + PAHs, Cu + Cd, and Cu + Cd + PAHs) on the development and morphological features of Macrocystis pyrifera sporophytes over a period of 90 days. Additionally, we determined the effects on the community structure associated with this kelp. This study evidenced a smaller number of blades and a decreased size of blades and holdfasts, as well as the death of individuals exposed to a secondary mix of metals (Cu + Cd) and a tertiary mix of pollutants (Cu + Cd + PAHs). Regarding the effects on the accompanying fauna, low richness and diversity were registered. M. pyrifera grazers, according to the mixture of pollutants, were either absent or diminished. These results show that the pulse of contamination in the early stages of M. pyrifera negatively affects its development and morphometry, as well as its role as an ecosystem engineer, due to a negative alteration in the species composition.

The influence of different types of reactant ions on the ionization behavior of polycyclic aromatic hydrocarbons in corona discharge ion mobility spectrometry

Some polycyclic aromatic hydrocarbons (PAHs) are considered to be cancer-causing chemicals, and ion mobility spectrometry (IMS) is used for on-site detection of such hazardous chemicals. In IMS, the ionization behavior of analytes is affected by the types of reactant ions (RIs). In the present work, the influence of different types of RIs on the ionization behaviors of PAHs in an ion mobility spectrometer equipped with a corona discharge ionization source was investigated using various RIs. Selected PAHs were dissolved in anisole, fluorobenzene, chlorobenzene, or bromobenzene. The IMS analysis procedure was performed as follows: (a) the PAH solution was dropped onto the smear matrix; (b) the smear matrix was immediately inserted into the sample inlet to minimize evaporation of the solvent; and (c) the IMS analysis was performed. The lowest amount studied was 10 ng. Variations in the IMS spectra with time were investigated. PAHs were not ionized by RIs of protonated molecules ([M + H]+ ) such as air/moisture and acetone, but they were ionized by charge transfer reactions with RIs of molecular ions (M•+ ) of solvents such as anisole, fluorobenzene, chlorobenzene, and bromobenzene. The PAH ions were detected following a time delay of ~1-5 s after the sample introduction, and the times at which the maximum intensities for the PAHs were observed were different. The detection limits of PAHs in chlorobenzene were on the whole better than those in other solvents, whereas those in fluorobenzene were worse. The detection limits of pyrene and benzo[a]anthracene were better than those of the other PAHs irrespective of the solvent used. PAH molecules were ionized by charge transfer reactions with RIs of the solvents, and their ions were detected ~1-5 s after sample introduction. The order of the ionization efficiency was chlorobenzene > anisole > bromobenzene > fluorobenzene.

Ratiometric SERS detection of polycyclic aromatic hydrocarbons assisted by β-cyclodextrin-modified gold nanoparticles.

A surface-enhanced Raman scattering (SERS) method is described for the determination of trace polycyclic aromatic hydrocarbons (PAHs) in the environment efficiently and economically. Detection sensitivity is improved by modifying gold nanoparticles (AuNPs) with 4-mercaptophenylboronic acid (4-MPBA) conjugated toβ-cyclodextrin (β-CD) as a new method for ratiometric determination of PAHs in solution. Pyrene (with a Raman band at 580cm-1) and anthracene (750cm-1) were used as the model analytes, while 4-MPBA (1570cm-1) was used as the internal reference to normalize the SERS signals. The intensity ratios of pyrene/4-MPBA increase linearly in the 2 to 10nM pyrene concentration range, and the intensity ratios of anthracene/4-MPBA increase linearly in the 10 to 100nM anthracene concentration range. The detection limits are 0.4nM for pyrene and 4.4nM for anthracene. This method was applied to the determination of the two analytes in soil sample extracts and the recoveries of pyrene (at levels of 236ng∙g-1 and 170ng∙g-1) and anthracene (334 ng∙g-1 and 510ng∙g-1) agreed well with the results from GC-MS analyses. The good recovery rates (101.8% and 102.5% for pyrene and 106.4% and 101.7% for anthracene) confirmed the reliability of the method. Graphical abstract Schematic illustration of SERS signal enhancement of pyrene, as an example of polycyclic aromatic hydrocarbons, by β-cyclodextrin modified gold nanoparticles.

Chemical Oxidative Potential and Cellular Oxidative Stress from Open Biomass Burning Aerosol

Particulate matter (PM) exposure is a leading global human health risk. In this study, water-soluble oxidative potential (OP) and intracellular reactive oxygen and nitrogen species (ROS/RNS) production were measured for open biomass burning aerosol collected from the Brazilian Amazon. Compared to ambient samples collected from Atlanta and laboratory-generated secondary organic aerosol (SOA), biomass burning aerosol had comparable OP and induced higher levels of ROS/RNS. Compared to regressed OP ranges for biomass burning factors resolved using source apportionment in prior studies, the samples investigated in this study spanned a wider OP range, suggesting that concentration addition may not be applicable for OP measurements. The discrepancy between ROS/RNS estimated using laboratory polycyclic aromatic hydrocarbons (PAHs) solution mixtures and ROS/RNS measured for the water-soluble hydrophobic fraction of Amazon filter samples further supports this conclusion. These results have important implications as...

Influence of smear matrix types on detection behaviors and efficiencies of polycyclic aromatic hydrocarbons using ion mobility spectrometry

Influence of smear matrix types on detection behaviors and efficiencies of polycyclic aromatic hydrocarbons (PAHs) with different molecular weights in ion mobility spectrometry (IMS) were investigated. Various smear matrices of stainless steel mesh (SM), cellulose paper (CP), and cotton fabric (CF) were employed. Anisole was used as the solvent and IMS analysis was performed without evaporation step of the solvent to apply charge transfer reactions between PAH molecules and the molecular ions of solvent. Shapes of reactant ion peaks (RIPs) were varied according to the smear matrix types. At the beginning of the sample inlet, intensity of RIPs of air and moisture notably decreased due to the lots of solvent vapor. The SM with good gas permeability showed relatively strong RIPs of air and moisture, whereas the CP with no gas permeability showed weak ones. Detection times and efficiencies of PAH ions were varied according to the smear matrix types as well as the kinds of PAHs. PAHs were on the whole detected well in 1–3 s after the sample inlet. Detection limits of PAHs measured using the SM were slightly better than those measured using the CP, while those measured using the CP were much better than those measured using the CF. The experimental results could be explained by structures of the smear matrices and evaporation behaviors of the PAH solutions.

Pulse UV light effect on microbial biomolecules and organic pollutants degradation in aqueous solutions

This study present assessed the effect of UV pulsed light (PL) on microbial and organic pollutants using two spiral lamps were used, i.e., PL1 and PL2 lamps, with wavelength cut-offs of 190 and 240 nm, respectively. Overall, our study demonstrated that pulsed UV light impacts several microbial biomolecules and degrades polycyclic aromatic hydrocarbons (PAHs) in aqueous solution. In microbial inactivation by PL2, temporary changes of bacterial cellular components, specifically proteins, were observed, but the compositional changes of bacteria that were exposed to PL1 were permanent due to ozonolysis. PL1 irradiation caused greater deactivation of the bacteria than PL2 irradiation due to the generation of ozone. The higher efficacy of PL1 in terms of membrane disruption, reduction of respiration rate, and reduction of growth rate was due to the production of ozone during the irradiation period. The bacteria that were irradiated with both PL lamps regrew due to photoreactivation, such as an enzymatic DNA-repair mechanism.The PAH degradation kinetics indicate that higher molecular weights degraded faster than those with lower molecular weights. For both lamps, the degradation of naphthalene and fluorene was first order, whereas second order for pyrene and anthracene. Any effect of ozonolysis on the PAH degradation rates was not apparent, which indicated that photolysis was the primary degradation pathway. PAH solutions treated with both pulsed UV lamps did not result in a toxicity effect on the bacteria.

A Highly Sensitive Dispersive Microextraction Method with Magnetic Carbon Nanocomposites Coupled with Dispersive Liquid–Liquid Microextraction and Two Miscible Stripping Solvents Followed by GC–MS for Quantification of 16 PAHs in Environmental Samples

In this work, a highly sensitive solid-phase-dispersive microextraction method was designed based on magnetic carbon nanocomposites as a magnetic solid-phase extraction sorbent coupled with dispersive liquid–liquid microextraction and two miscible stripping solvents (MSPE–DLLME) followed by gas chromatography–mass spectrometry (GC–MS) for determination of 16 polycyclic aromatic hydrocarbons (PAHs). By adopting this research methodology, a mixture of two miscible organic solvents is used not only as stripping solvent for MSPE, but also as extraction and disperser solvents for DLLME procedure. Several parameters such as amount of extraction adsorbent, type of stripping, extraction solvents and their volumes, salt effect, and pH and volume of sample solution were optimized to obtain high extraction recoveries. Finally, 2 µL of extraction phase was injected into GC–MS. Under optimal conditions, the method attained satisfactory precisions (RSD% ≤ 8.66), excellent limits of detection in the range of 0.1–0.5 ng kg−1 at S/N = 3, and very high enrichment factors in the range of 28,187–33,149 for 500 mL sample solution of different PAHs. The calibration curves of 16 extracted PAHs were linear in the range of 0.4–10,000 ng kg−1, with coefficients of determination (r2) between 0.9989 and 0.9999. The optimized method to determine 16 PAHs has been successfully applied in the real environment including waters, waste water, sewage, and soil.

Degradation of polycyclic aromatic hydrocarbons in contaminated soil by immobilized laccase

The biodegradation of polycyclic aromatic hydrocarbons (PAHs) in soils by laccase is reported. However, the low laccase activities of free laccase have limited its applications in environmental bioremediation. In this study, polluted soil was made with 3:1 volume ratio of soil to PAH solution. Subsequently, the adsorption?cross-link composite immobilization method was applied to immobilize laccase derived from fungi onto nylon net and chitosan, respectively. These two kinds of immobilized laccase were used in the degradation of pyrene (Pyr) and benzo[a]pyrene (BaP), and their degradation efficiencies under different temperature and pH conditions were investigated. Consequently, the optimal laboratory experimental parameters were determined as follows: first, compared with free laccase, the degradation rates of Pyr and BaP by immobilized laccase increased by around 10?30 %; second, the degradation efficiency of chitosan as a carrier of immobilized laccase was much better than that of nylon net as a carrier of the immobilized laccase; finally, when the temperature was set at 40?C and the pH was set at 4, the degradation efficiency achieved by immobilized laccase was the best.

Exploration of pyrazine-embedded antiaromatic polycyclic hydrocarbons generated by solution and on-surface azomethine ylide homocoupling

Nanographenes, namely polycyclic aromatic hydrocarbons (PAHs) with nanoscale dimensions (>1 nm), are atomically precise cutouts from graphene. They represent prime models to enhance the scope of chemical and physical properties of graphene through structural modulation and functionalization. Defined nitrogen doping in nanographenes is particularly attractive due to its potential for increasing the number of π-electrons, with the possibility of introducing localized antiaromatic ring elements. Herein we present azomethine ylide homocoupling as a strategy to afford internally nitrogen-doped, non-planar PAH in solution and planar nanographene on surfaces, with central pyrazine rings. Localized antiaromaticity of the central ring is indicated by optical absorption spectroscopy in conjunction with theoretical calculations. Our strategy opens up methods for chemically tailoring graphene and nanographenes, modified by antiaromatic dopants.

Determination of PAHs in Solution with a Single Reference Standard by a Combination of 1H Quantitative NMR Spectroscopy and Chromatography.

We have applied a combination of 1H quantitative NMR spectroscopy (1H-qNMR) and chromatography (GC or LC) to establish reliable analytical methods (qNMR/GC and qNMR/LC) for organic compounds. In this method, a reference standard is used as an internal standard for both 1H-qNMR and chromatography to estimate relative molar sensitivity (RMS) for analytes. The RMS values are calculated from the molar ratios between analytes and the reference standard obtained by 1H-qNMR; and the response ratio between them obtained by chromatography. Concentrations of analytes in the organic solution can be simultaneously determined from the RMS and amount of the reference standard added in the sample solution. This analytical method is an innovative one because only one reference standard with International System of Units (SI)-traceable property value, purity, or concentration, is necessary to determine accurate concentrations of multiple organic components in organic solutions, without the respective certified reference standards for various analytes. To verify this method, a certified reference material, NIST SRM 1647f, was used. Among the 16 polycyclic aromatic hydrocarbons (PAHs) included in NIST SRM 1647f, naphthalene and benzo[a]pyrene were selected as analytes for this method, using 1,4-bis(trimethylsilyl)benzene-d4 as the reference standard. Each quantitative value obtained by qNMR/GC and qNMR/LC agreed with each certified value within its expanded uncertainty.

Synthesis and characterization of a molecularly imprinted polymer for the isolation of the 16 US-EPA priority polycyclic aromatic hydrocarbons (PAHs) in solution

A smart sorbent consisting of benzo[k]fluoranthene-imprinted and indeno[1 2 3-cd]pyrene-imprinted polymers mixed at 1:1 (w/w) was successfully screened from several cavity-tuning experiments and used in the isolation of polycyclic aromatic hydrocarbons from spiked solution. The polymer mixture showed high cross selectivity and affinity towards all the 16 US-EPA priority polycyclic aromatic hydrocarbons. The average extraction efficiency from a cyclohexane solution was 65 ± 13.3% (n = 16, SD). Batch adsorption and kinetic studies confirmed that the binding of polycyclic aromatic hydrocarbons onto the polymer particles resulted in formation of a monolayer and that the binding process was the rate limiting step. The imprinted polymer performance studies confirmed that the synthesized polymer had an imprinting efficiency of 103.9 ± 3.91% (n = 3, SD). A comparison of the theoretical number of cavities and the experimental binding capacity showed that the overall extent of occupation of the imprinted cavities in the presence of excess polycyclic aromatic hydrocarbons was 128 ± 6.45% (n = 3, SD). The loss of selectivity was estimated at 2.9% with every elution cycle indicating that the polymer can be re-used several times with limited loss of selectivity and sensitivity. The polymer combination has shown to be an effective adsorbent that can be used to isolate all the 16 US-EPA priority polycyclic aromatic hydrocarbons in solution.