A multivariate study of the programmed temperature vaporization injection-gas chromatographic-mass spectrometric determination of polycyclic aromatic hydrocarbons Application to marine sediments analysis

The trace analysis of polycyclic aromatic hydrocarbons (PAHs) in environmental matrices requires highly sensitive and selective methods. The use of large-volume injection in gas chromatography with mass spectrometry detection allows the improvement of the sensitivity. In this work, one of the most popular large-volume injectors, programmed temperature vaporization (PTV)-splitless injection, was optimized to determine 26 alkylated and non-alkylated PAHs at ultratrace levels. The injection conditions that use two different injection volumes, 10 and 25 μl, were optimized applying experimental designs. Six experimental factors that could affect the vaporization efficiency were studied. Detection limits for each assayed volume were compared with splitless injection, both in full scan and in SIM mode. An improvement of 50- and 100-fold, for 10 and 25 μl, respectively, was achieved for PAHs in comparison with splitless injection. Finally, the method that was optimized for 25 μl was applied successfully to the analysis of a certified marine sediment SRM 1941b and a real marine sediment extracted by microwave assisted extraction.     

Level of Polychlorinated Biphenyls in Marine Environment of Algiers Bay,Algeria

Polychlorinated Biphenyls (PCBs) are persistent organic pollutants with significant bioaccumulation in the global environment. Owing to their high toxicity and lipophilic property, PCBs are potential threat to the human and ecological system.

The objective of this work was to investigate the polychlorinated biphenyls in seawater and blue mussels Mytilus galloprovincialis collected in the eastern coastal side of the Algiers bay. Surface and bottom water samples were collected at six different periods from July to October 2002 in the port of Tamentfoust and four locations around the port. Mussel samples were collected from Tamentfoust port and Surcouf beach. After extraction, the PCBs levels were determined in marine water and biological samples by gas chromatography with electron capture detector. Total polychlorinated biphenyls concentrations varied from 4.0 to 18.8 ng · L^?1 in surface and from 4.4 to 16.6 ng · L^?1 in bottom seawater and were relatively high in August (30th and 45th days).

In mussels that concentrate the organochlorinated compounds in their tissues, the sum of ICES 7 PCBs concentrations was relatively high. It ranged from 64.2 to 185.8 ng · g^?1 dw (average 125.8 ng · g^?1 dw) in samples collected from Surcouf. The level of contamination in Tamentfoust port mussels was about twice higher (225.2 ng · g^?1 dw).

The observed PCBs distribution was close to that of common commercial mixture and suggests an industrial origin of this pollution emitted from a continental source in addition to the port activities. Although the use of target compounds has been banned for more than three decades, they are still persistent in Algiers Bay.     

Development of solid-phase microextraction to study dissolved organic matter—Polycyclic aromatic hydrocarbon interactions in aquatic environment

Solid-phase microextraction coupled with gas chromatography and mass spectrometry (SPME–GC–MS) was developed for the study of interactions between polycyclic aromatic hydrocarbons (PAHs) and dissolved organic matter (DOM). After the determination of the best conditions of extraction, the tool was applied to spiked water to calculate the dissolved organic carbon water distribution coefficient (K_DOC) in presence of different mixtures of PAHs and Aldrich humic acid. The use of deuterated naphthalene as internal standard for freely dissolved PAH quantification was shown to provide more accuracy than regular external calibration. For the first time, K_DOC values of 18 PAHs were calculated using data from SPME–GC–MS and fluorescence quenching; they were in agreement with the results of previous studies. Competition between PAHs, deuterated PAHs and DOM was demonstrated, pointing out the non-linearity of PAH–DOM interactions and the stronger interactions of light molecular weight PAHs (higher K_DOC values) in absence of high molecular weight PAHs.     

Simplified procedures for the analysis of polycyclic aromatic hydrocarbons in water, sediments and mussels

We describe in this paper simple and robust analytical protocols to determine the 16 polycyclic aromatic hydrocarbons (PAHs) of the US Environmental Protection Agency priority list in water, sediment and mussels. For water samples, eight different solid-phase extraction (SPE) sorbents have been compared and among them, C18 provided highest recoveries and limits of detection of 0.3-15 ng/L. For lyophilized sediments, Soxhlet and ultrasonic extraction were compared, and the last one permitted to recover all analytes with highest repetitivity and was validated by analysing a certified reference material. Finally, the analysis of mussels was undertaken using Soxhlet, ultrasonic and pressurized liquid extraction (PLE) and the performance of several clean-up steps are compared. Whereas for the former two, incomplete recovery or losses of some analytes were evidenced, PLE permitted a more efficient extraction and although alkaline digestion was necessary to remove coextracted compounds, the method gave acceptable recoveries and limits of detection of 0.5-7.7 microg/kg dry mass, as for sediments. In all cases, analysis was performed by gas chromatography coupled to mass spectrometry and internal standard quantification was performed using five deuterated PAHs. Each method performance is discussed for the three matrices analysed and the paper reports advantages and disadvantages of each for their routine application in monitoring programs.     

Accelerated extraction for determination of polycyclic aromatic hydrocarbons in marine biota

A rapid and simple method is proposed for determination of polycyclic aromatic hydrocarbons (PAH) in complex matrices such as marine biota. The method uses sonication, by means of an ultrasonic probe, as a new tool for assisted extraction, coupled with reversed-phase liquid chromatography (RP-LC) with fluorescence detection (FL) for determination of 16 US EPA priority PAH. Separation and detection of the 16 PAH were complete in 45 min by RP-LC with a C₁₈ column and acetonitrile–water gradient elution. Multivariate optimisation of the variables affecting extraction (ultrasound radiation amplitude, sonication time, and temperature of the water-bath in which the extraction cell was placed) was conducted. The accuracy of the method was determined by analysis of a certified reference material and comparison of the results obtained with those from another method (microwave-assisted extraction and GC–MS). The new technique avoids the main problems encountered in the determination of PAH in complex matrices such as marine biota, and no clean-up step is necessary. The method was applied to determination of PAH in estuarine biota samples from the Urdaibai estuary (Biscay, Spain).     

Biodegradability of nylon 4 film in a marine environment

Biodegradability of nylon 4 in seawater from Tokyo Bay was investigated by weight loss and biochemical oxygen demand (BOD) of nylon 4 films. The remaining weight of nylon 4 film decreased with incubation time in the seawater, and the percentage of weight loss of nylon 4 film was 30% after 3 weeks. BOD biodegradability of nylon 4 film was approximately 80% within 25 days. Scanning electron microscopy images of the nylon 4 film before and after the seawater treatment revealed that the surface of the nylon 4 films was eroded after biodegradation in seawater. The average molecular weights of the nylon 4 films indicated no significant difference between before and after 30% weight loss of the film. Based on the present data, nylon 4 film was degraded on the surface of the film in the seawater. Furthermore, microbial degradation seemed to be one of the main degradation mechanisms of nylon 4.     

Measurement of arsenic species in marine sediments by high-performance liquid chromatography-inductively coupled plasma mass spectrometry

Extraction of sediments with phosphoric acid (0.5 M) and hydroxylamine hydrochloride (0.1 M) allowed the measurement of labile arsenic species while preserving the two redox states of arsenic. The forms and concentrations of arsenic species were measured using HPLC-ICP-MS. A Hamilton PRP X-100 strong anion exchange column using a 20 mM ammonium phosphate buffer (pH 6 and 9.2) was used to separate arsenic species. Recoveries of sediments spiked with As(V) were quantitative whereas for sediments spiked with As(III) recoveries of between 89 and 104% were obtained from four oxic certified reference sediments and an anoxic sediment. Application of the method to sediment samples from the marine Lake Macquarie, NSW, Australia, indicate that anoxic sediments can contain high concentrations of As(III), and two arsenosugars (sulfonate-ribose and sulfate-ribose). Extraction efficiencies for arsenic ranged between 6 and 82%. The arsenic species measured in sediments are strongly depended on the extraction procedure used. As(III) and arsenosugar concentrations in sediments that were freeze dried and oxidised were much less than in sediments that were not freeze dried and when exposure to air was keep to a minimum. Corresponding, As(V) concentrations tended to be higher in samples that were exposed to air.     

Polycyclic aromatic hydrocarbons with five-membered rings: Modeling of experimental X-ray and neutron-diffraction structures

Several of the readily available theoretical programs are evaluated as tools for modeling the structures of polycyclic aromatic hydrocarbons with five-membered rings (CPAHs). The experimentally determined bond lengths and angles are compared to calculated values. Experimental bond lengths are also compared to Pauling and Huckel molecular orbital (HMO) bond orders. Previously published experimental X-ray and neutron-diffraction structures of acenaphthene, acenaphthylene, fluoranthene, cyclopent[o,p,q,r]benz[c]phenanthrene, and corannulene are modeled by the programs MMX, AM1, MNDO, and PM3, and previously reported STO-3G and 6-31G * data are also evaluated. In general, the error differences between the experimental and calculated results for all of the semiempirical programs were small. However, PM3 performed slightly better than AM1 and MMX, while MNDO generated structures which exhibited the largest deviation from experiment. Although the standard deviations for all programs are shown to be of comparable magnitude, a particular bond length or bond angle in any given theoretical calculation can exhibit significant error from the experimental data. The scatter in the bond order data computed from Huckel molecular orbital theory and valence bond theory is contrary to results obtained with alternant systems. It appears that these approaches are less successful at modeling accurately the nonalternant hydrocarbon systems described in this paper.     

Fe analysis by the ferrozine method: Adaptation to FIA towards in situ analysis in hydrothermal environment

The target of this study is the adaptation of the ferrozine method to flow injection analysis (FIA) to perform iron analysis in situ using an in situ chemical analyser in hydrothermal environments. The adaptation of the method to FIA was followed by its optimisation using an experimental design screening method. The goals of the optimisation steps were to decrease the detection limit and to increase the measuring range to cope with the constraints of in situ analysis. The method allows the determination of iron in the mixing zone of hydrothermal fluid, enriched in iron, and seawater. A single manifold gives the possibility to analyse either Fe(II) or ΣFe [Fe(II) + Fe(III)] in situ, or ΣFe in the lab on hydrothermal seawater samples. The measuring range of the method was increased to up to 2000 μM, which is coherent with the study of the chemical environment of communities associated with deep-sea hydrothermal activity. Finally, the method was applied in situ using the chemical analyser Alchimist during the ATOS cruise on hydrothermal vent fields on the Mid Atlantic Ridge.     

Microwave-assisted extraction of organochlorine compounds in marine sediments with organized molecular systems

Summary Analysis of marine sediments is particulary important because they are considered pollution indicators, since they present a view of the spatial distribution of pollutants. The use of microwave energy enables a simple and rapid analysis of different kinds of compounds present in these media. This work shows the results obtained during the optimization process for the application of microwave-assisted extraction methodology (MAE) to the determination of polychlorinated dibenzofurans (PCDFs), present in different marine sediment samples, as well as in mixtures with polychlorinated biphenyls (PCBs), using two non-ionic surfactants (oligoethylene glycol monoalkyl ether and polyoxyethylene 10 lauryl ether) as extractants. After extraction, the organochlorinated compounds are determined by HPLC using fluorescence detection. Recovery rates are compared with those obtained when Soxhlet extraction is used for the same purpose.     

Titanium as a chemical modifier for the determination of cobalt in marine sediments

The determination of cobalt in marine sediments by electrothermal atomic absorption spectrometry was studied using no modifier and magnesium and titanium as modifiers. Titanium is one of the major sediment constituents, which widely affects the cobalt determination and it was studied as a chemical modifier since it was the only concomitant that increased the cobalt signal in the concentration range usually found in sediments. The performance of Mg and Ti as chemical modifiers was compared relative to maximum pyrolysis and atomization temperatures, linear calibration range, sensitivity and matrix effects. The pyrolysis curves showed that the analyte could be stabilized up to 1400 °C when either Ti or Mg(NO₃)₂ was present, while only 1000 °C could be used in the absence of a modifier. The optimum atomization temperature was 2500 °C in all cases. Analytical curves were compared using no modifier, 5 μg Ti and 100 μg Mg(NO₃)₂ as modifiers, and the linear range found was up to approximately 4 ng Co whether a modifier was used or not. With Ti as a chemical modifier, analytical curves for cobalt in aqueous solution and in a synthetic matrix resulted in the same sensitivity (m₀=55 pg), whereas the use of Mg led to characteristic mass values of 59 and 72 pg in aqueous solution and in a synthetic matrix, respectively, showing some matrix effect. The detection limits (3σ, n=10) were 0.4 μg g⁻¹ using no modifier and 0.3 μg g⁻¹ with Ti as a modifier in the original matrix. A reference estuarine sediment NIST 1646 with a non-certified content of 10.5 μg g⁻¹ Co was analyzed and the found value of 10.9±2.4 μg g⁻¹, (n=3), using Ti as chemical modifier and calibration against aqueous standards, was in good agreement with the recommended value.     

Factors affecting the reversed-phase liquid chromatographic separation of polycyclic aromatic hydrocarbon isomers

Reversed-phase liquid chromatography (LC) on C₁₈ stationary phases provides excellent selectivity for the separation of polycyclic aromatic hydrocarbons (PAH). Recent studies have shown that several factors affect selectivity for the LC separation of PAH including phase type (monomeric or polymeric), pore diameter and surface area of the silica substrate, and surface density of the C₁₈ ligands. In this paper the separation of eleven PAH isomers of molecular weight 278 is used to further illustrate the effect of stationary phase characteristics and shape of the solute (length-to-breadth ratio, L/B) on retention and selectivity. Only polymeric C₁₈ phases with a high C₁₈ surface coverage provided separation of all eleven isomers and the elution order of these isomers generally followed increasing L/B values. The effect of solute nonplanarity on reversed-phase LC retention was investigated on both monomeric and polymeric phases using a series of planar and nonplanar PAH pairs. For each solute pair, the nonplanar solute eluted earlier than the planar solute, the largest selectivity factors being observed on the C₁₈ phase with the highest percent carbon load. Based on these studies, a model is proposed to describe the retention of PAH on polymeric C₁₈ phases.     

A review of monitoring of airborne polycyclic aromatic hydrocarbons: An African perspective

In this review, we focus on the status of the monitoring of polycyclic aromatic hydrocarbons (PAHs) in ambient air as well as in living (indoor) and working environments in Africa from 2000 to 2018. This is important as PAHs are ubiquitous in the environment and are known to be potentially carcinogenic. Aspects of sampling such as collection media for particle bound and gaseous PAHs are discussed. The efficiency and basic quality assurance data of commonly employed extraction techniques for separating target PAHs from sampling media using conventional solvent-based and emerging solvent-free approaches were also evaluated. Polyurethane foam and quartz fiber filters are generally the most commonly used collection media for gaseous and particle bound PAHs, respectively. A wide range of total PAH concentrations in ambient air has been reported across the continent of Africa, with the highest levels found at sampling sites close to high density traffic and industrial areas. A rapidly increasing population, commercial and industrial development, poor urban transportation infrastructure and the use of low quality oil products were the main causes of high total gas and particulate PAH concentrations (1.6–103 μg/m³) in West African port cities such as Cotonou, Benin. With regards to indoor environments, gas phase PAHs were detected at the highest total concentrations in rural areas ranging from 1 to 43 μg/m³ in Burundi with naphthalene being the most prevalent. Firewood burning was the major emission source in most developing countries and resulted in benzo[a]pyrene concentrations above the European permissible risk level of 1 ng/m³.     

Levels of polycyclic aromatic hydrocarbons,polychlorinated byphenyls,methylmercury and butyltins in the natural UNESCO reserve of the biosphere of Urdaibai (Bay of Biscay,Spain)

Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), methylmercury (MeHg⁺) and butyltins (mono-, di- and tri-butyltin, MBT, DBT and TBT) were monitored in oysters (Crassostrea sp.) and sediments collected in different sampling points of the UNESCO reserve of the biosphere of Urdaibai (Bay of Biscay) from March 2006 to June 2007. In the case of oyster samples, concentrations in the 290–1814 µg kg^?1 (PAHs), 70–475 µg kg^?1 (PCBs), 75–644 µg kg^?1 (MeHg⁺) and 200–1300 µg kg^?1 (as a sum of the three butyltins) ranges were obtained. In most samples TBT was the most abundant butyltin, followed by DBT and MBT. It should be highlighted that most samples exceeded the highest range (367 µg kg^?1) found in the last mussel watch programme carried out by the National Oceanic and Atmospheric Administration (NOAA) for butyltins in oyster samples. This could be due to the presence of a shipyard in the estuary. Sediment concentrations ranged as follows: total PAHs (856–3495 µg kg^?1) and total PCBs (58–220 µg kg^?1). Organometallic species were always below the limits of detection (LODs) (0.24 µg kg^?1 for MeHg⁺, 0.6 µg kg^?1 for MBT, 0.48 µg kg^?1 for DBT and 1.1 µg kg^?1 for TBT). In both sediment and oyster PAH sources were mostly combustion. In the case of PCBs, 4-6 chlorine-atom congeners were the most abundant ones. Slight differences in the profile of PAHs as well as PCBs can be detected when the matrices were compared with each other. Finally, in the case of PAHs, sediment and water column played the main role in the accumulation pathway into the organisms in all the sampling stations.     

Assessment of oil contamination in the marine environment by pattern recognition analysis of paraffinic hydrocarbon content of mussels

Data on the paraffinic hydrocarbon content of mussels (Mytilus edulis and M. califomianus) were analyzed statistically in an attempt to assess oil contamination of several aquatic areas of the greater Puget Sound basin in the State of Washington. The mussels were collected quarterly over a period of two years from ten locations. Fundamental statistical treatment of the data did not reveal meaningful trends. Application of pattern recognition techniques to the hydrocarbon data set allowed the mussel samples to be successfully classified into groups, from areas near known sources of potential pollution or from areas remote from known pollution. Several samples however, could not be grouped consistently as either from contaminated or uncontaminated sites. In addition, the mussels from a particular area could be separated as to season of sampling. Seasonal variation in levels of individual paraffinic hydrocarbons were greater than annual changes. The n-C₁₆ hydrocarbon concentration was the most useful of the 34 features studied for establishing possible oil contamination of the areas. The n-C₁₆ hydrocarbon content was also used successfully to detect oil spills and to define uncontaminated locations in Puget Sound.     

Distribution and fate of tributyltin in the united states marine environment

Tributyltin (TBT) has been measured in water in 12 of 15 harbors studied during US Navy baseline surveys. The highest concentrations of TBT (some exceeding laboratory toxicity limits) have been found in yacht harbors and near vessel repair facilities. Many sites (75%) in harbors and estuaries had no detectable (<5 ng dm^?3) TBT. TBT monitoring studies with increased detection limits (<1 ng dm^?3) have documented a high degree of TBT variability associated with tide, season and intermittent point source discharges. Although yacht harbors were shown to be the principal TBT source in most regions, dry-docks can be significant sources. Tributyltin degradation studies were conducted using unfiltered seawater from four geographic regions and incubated under natural conditions. Degradation half-lives were always in the range of 4–19 days, providing evidence that TBT is not highly persistent in the water column at environmental concentrations. Preliminary degradation experiments suggest that TBT has a longer residence time in sediment with a half-life of several months. Tributyltin is primarily in the dissolved form in unfiltered seawater, although the association with particulate fractions may increase in samples collected near yacht repair facilities, Partition coefficients for particulate TBT versus bulk water are frequently near 3000 and vary with the particulate concentration, salinity and presence of natural organics.     

Identification and quantitative analysis of nitrogen-containing polycyclic aromatic hydrocarbons in sediments

An integrated analytical methodology has been developed for determining nitrogen-containing polycyclic aromatic hydrocarbons, which enables quantitation of individual contaminants as low as 1 μg/kg in sediment samples. A cross-sectional profile from the Hamilton Harbour sediment samples was analyzed for azaarenes. These contaminants were separated by Soxhlet extraction, and pH adjustment allowed their isolation from different classes of neutral and acidic components. Separation and identification of the organic bases in each sample were achieved by using open tubular column gas chromatography with thermionic detection and HRGC-mass spectrometry. Organic bases present in the samples included mostly azaarenes such as acridines, benzacridines, azafluorene, benzoquinolines, azapyrenes, etc. Quantitation and environmental significance of these compounds are discussed. Recoveries of individual azaarenes at two different levels were evaluated. Data presented indicate that detection limits of this method are between 1 and 10 μg/kg. Recovery azaarenes from bottom sediment samples at concentration levels between 1 to 100 μg/kg is 81 ± 17%.     

Polycyclic aromatic and aliphatic hydrocarbons in Mytella charruana, a bivalve mollusk from Mundaú Lagoon, Brazil

The levels of selected organic markers, such as 17 polycyclic aromatic hydrocarbons (PAHs), 16 of which are classified as priority pollutants by the US-EPA, perylene, aliphatic hydrocarbons (linear alkanes) and petroleum biomarkers (hopanes and steranes) were assessed in Mytella charruana, a common bivalve mollusk from the convergence of the Mundaú Lagoon, Maceió, Alagoas, Brazil. The organic markers were evaluated in three campaigns (Jul/2006, Oct/2007 and Feb/2008) aiming to identify pollution sources, understand their status of contamination and determine baseline data looking for future management strategies. Higher Σ16HPAs concentration was observed in organisms with 10-30 mm (80% of the total mass of organisms from Mundaú Lagoon) collected in Feb/2008, whereas in individuals with 30-40 mm, the PAH concentrations were higher during Jul/2006 and Oct/2007. The sugarcane burning in Maceió-AL occurs between October and March. The Flt/(Flt + Py) and BaA/(BaA + Chry) ratios in Feb/2008 indicated a combustion process source. The PAH concentrations in Mytella charruana are below of the limit value considered by the WHO (10 ng g⁻¹ for BaP). However, the results suggest that the sugarcane burning process lead to higher PAH concentrations in these organisms in Feb/2008. Many samples showed significant contamination by petroleum biomarkers, hopanes and steranes. Also, the aliphatic hydrocarbon chromatographic profiles were characteristic of petrogenic sources. The hydrocarbons measured in Mytella charruana from Mundaú Lagoon seems to be impacted by PAH in sugarcane burning periods. On the other hand, urban residues and fishing boats could be pointed as important petrogenic sources of aliphatic hydrocarbons in the same bivalve mollusk.     

Isotope dilution analysis mass spectrometry for the routine measurement of butyltin compounds in marine environmental and biological samples

The highly qualified primary method of species-specific isotope dilution analysis has been employed in this work to evaluate for the first time the levels of butyltin compounds in the estuary of the river Eo (Northwest Spain) where there is, since many years, a high oyster farming activity. A spike solution containing mono-, di- and tributyltin enriched in ¹¹⁹Sn allowed the simultaneous determination of the three compounds in different marine environmental and biological samples collected in this area (seawater samples, sediments and biological tissues of four different marine species). The results obtained in this work showed toxic TBT levels for many marine species in 45% of the seawater samples analyzed whereas significant organotin concentrations were found to be obtained only in one of the sediments analyzed. On the other hand, TBT levels ranging from 20 to almost 200 ng g^− 1 (dry weight) were obtained in the different biological tissues analyzed demonstrating the bioaccumulation of organotin compounds in certain marine species.