The Application of Perdeuterated Polycyclic Aromatic Hydrocarbons (PAH) as Internal Standards for the Liquid Chromatographic Determination of PAH in a Petroleum Crude Oil and Other Complex Mixtures

Abstract

A sequential liquid chromatographic (LC) procedure for the determination of polycyclic aromatic hydrocarbons (PAH) in a petroleum crude oil and other complex mixtures is described. The procedure includes normal-phase LC on an aminosilane column to isolate fractions containing isomeric PAH and reversed-phase LC on a polymeric C₁₈ column to separate the individual PAH isomers. Appropriate perdeuterated PAH are added to the sample so that each isomeric fraction will contain one internal standard. The perdeuterated PAH are excellent internal standards for this sequential LC procedure. Perdeuterated PAH have normal-phase and reversed-phase LC retention characteristics similar to those of the parent PAH. In the normal-phase LC separation, the perdeuterated PAH elute in the same fraction as the parent PAH. In the reversed-phase LC separation, the perdeuterated PAH elute first and are generally resolved from the parent PAH. The optimized spectrofluorometric detection of each PAH analyte is accomplished by programming appropriate sets of excitation and emission wavelengths to correspond with the elation time of each analyte on the polymeric C₁₈ column. The analytical results obtained from this procedure for the analysis of a shale oil sample [Standard Reference Material (SRM) 1580] and a petroleum crude oil (SRM 1582) are compared to values obtained by gas chromatography - mass spectrometry.     

Identification Of Oxygen Derivatives Of Polycyclic Aromatic Hydrocarbons In Airborne Participate Matter Of Upper Silesia (Poland)

Abstract

Organic material extracted from airborne participate matter collected in various places of Upper Silesia has been separated by column liquid adsorption chromatography. Six fractions of different polarity have been eluted. These fractions have undergone careful spectral analysis, thin layer chromatography and gas chromatography-mass spectrometry. Several PAH oxygen derivatives which have not been found in air from our Region so far were identified. Their biological activity is higher than activity of basic PAH structures. These compounds can be responsible to a high degree for interference in living organism functions in this highly polluted region.     

The Determination of Polycyclic Aromatic Hydrocarbons in Indigenous and Transplanted Mussels (Mytilys Edulis L.) Along the Dutch Coast

Abstract

A method, originally developed to investigate the pollution of Dutch coastal water with metals and PCBs,¹ was modified for the determination of the pollution with polycyclic aromatic hydrocarbons (PAH).

The method is based on active biological monitoring with mussels (Mytilus edulis L.). Its usefulness has already been demonstrated.² In the present study a method for the determination of PAH in mussels has been developed. The method is based on the hydrolysis of tissue with 4 M sodium hydroxide, extraction with hexane, clean-up with 10% deactivated aluminium oxide and quantitative determination with Reversed Phase High Performance Liquid Chromatography (RP-HPLC) and fluorescence detection.

The accumulation plateau of most of the PAH studied has not been reached after 60 days. Gradients of pollution were found, and at least one significant source near IJmuiden was detected.     

Analysis of Polycyclic Aromatics

Abstract

Polycyclic aromatic hydrocarbons (PAH), among them carcinogenic compounds, have been found to be widely distributed in the human environment. The formation of PAH in processes relevant to environmental pollution will be described (pyrolysis or incomplete combustion of aliphatic and aromatic material, formation in higher plants). The application of the following methods to the analysis of PAH mixtures will be discussed: gas chromatography (capillary columns, use. of liquid crystals and inorganic salts such as LiCl or Cacl₂, as stationary phases in packed columns, selective detectors); luminescence spectroscopy (use of phosphorescence in paper and thin-layer chromatography, Shpol'skii spectra, quenchofluorimetry; mass spectroscopy.     

Modification of Selectivity in Reversed-Phase Liquid Chromatography of Polycyclic Aromatic Hydrocarbons Using Mixed Stationary Phases

Abstract

Monomeric and polymeric C₁₈ materials provide significantly different selectivities for polycyclic aromatic hydrocarbons (PAH) in reversed-phase liquid chromatography. Selectivity factors vary in a regular manner with respect to surface concentration of C₁₈ groups on different C₁₈ columns. In this study, we investigated the feasibility of “customizing” a C₁₈ column to provide an intermediate selectivity by mixing 5-μm polymeric C₁₈ material from two different lots with high and low C₁₈ surface concentrations. Polymeric C₁₈ materials from different production lots were mixed in ratios of 30/70, 50/50, and 70/30 (w/w). Selectivity factors for these columns were found to be similar to those predicted by the linear addition of the selectivities of the two individual phases. The PAH selectivities on these mixed columns were also found to be comparable to data obtained from coupled short columns of appropriate lengths each containing one of these different C₁₈ materials. These studies indicate that columns of specific selectivity can be prepared by either mixing two different C₁₈ materials or by coupling columns containing each of these different phases. The use of mixed phase columns is illustrated for the analysis of a fraction containing five condensed ring PAH isomers (molecular weight 278) isolated from an air particulate sample.     

Direct Determination of Benzo(a)pyrene and Pyrene in Solid Environmental Samples by Jet-Cooled Spectroscopy

Abstract

We report the direct determination of two polycyclic aromatic hydrocarbons (PAH), Benzo(a)Pyrene [B(a)P] and Pyrene (Pyr), in solid environmental samples, i.e. a marine sediment and scrapings from the interior walls of a steel foundry, by the supersonic jet/laser induced fluorescence technique. We have found limits of detection (LOD) for these samples of 900ng (1.8ppm) for B(a)P and 200ng (0.4ppm) for Pyr. The LOD's for prepared solutions were 100 ng for B(a)P and 40 ng for Pyr. In validating the procedure we have also analyzed a standard mixture of PAH. The results of our analyses of the solid environmental samples agree well with those obtained by chromatography in other laboratories. We have found evidence of incomplete recovery of PAH from soil sediments by a prolonged low temperature Soxhlet extraction using methylene chloride.     

Environmental PAH analysis by gas chromatography–atmospheric pressure laser ionization–time-of-flight–mass spectrometry (GC-APLI-MS)

The application of polycyclic aromatic hydrocarbon (PAH) analysis by gas chromatography coupled with atmospheric pressure laser ionization and mass spectrometry (GC-APLI-MS) to environmental samples was investigated in the study. The limit of detection for 40 PAH in a standard mixture was 5–100 fg, demonstrating GC-APLI-MS to be a highly sensitive technique and more sensitive by a factor of 100–3,500 compared to GC-MS. Acenaphthylene and cyclopenta[cd]pyrene were not detectable <2,500 fg per injection. To make use of this very high PAH sensitivity, the technique was applied to samples of environmental interest with limited available sample amounts such as particulate matter (PM), soot and a sample from a bioaccumulation test with Lumbriculus variegatus. First, special sample preparation was necessary and ultrasonic extraction proved to be suitable, if a thorough clean-up was performed and plastic materials avoided. By GC-APLI-MS and GC-MS, 224 and 28 single PAH compounds were detected in PM, about 1,000 and 15 in birch soot, and 9 and 2 in worm tissue, respectively, revealing the enormous potential of the method. The selectivity of GC-APLI-MS was shown for a crude oil where >2,200 PAH were detected without any sample preparation.     

Column Switching Technique for Group-Type Separation of Different Pah Classes by use of C18-Modified Silica and Polystyrene Packings

Abstract

A column switching technique was developed to realize a group-type separation of PAHs and nitrogen containing PAHs (N-PAHs) applying a C₁₈-immobilized polystyrene packing as well as a C₁₈-modified silica stationary phase. On the first column the group-type separation and also the separation of the N-PAH fraction in single compounds was performed. After backflush and transfer to a second column, the separation of the PAH fraction could be achieved.     

Monitoring Method for Airborne Polycyclic Aromatic Hydrocarbons

Abstract

This paper describes a method for the determination of airborne polycyclic aromatic hydrocarbons (PAH), which has been employed in routine analysis of a large number of samples. The method is in principle based on well known techniques, but some improvements have been made in order to reduce the analysis time and the cost without lowering the quality of the analytical results. Recovery studies have been made for some important steps of the procedure, and the reproducibility of the sampler has been tested. The method has proved to be suitable for monitoring of PAH in highly polluted as well as pristine areas.     

The Identification of Polynuclear Aromatic Hydrocarbon (PAH) Derivatives in Mutagenic Fractions of Diesel Particulate Extracts

Abstract

The soluble organic fraction (SOF) of particulate matter from diesel exhaust (from point sources, ambient air, etc.) contains hundreds of organic constituents. Normal-phase high pressure liquid chromatography (HPLC) has been used to separate the SOF into sub-fractions suitable for subsequent chemical analysis and bioassays. These fractions consist of non-polar(PAH), moderately polar (transition) and highly polar constituents. The non-polar fractions have been well characterized and consist of PAH and aliphatic hydrocarbons. The specific compounds present in the transition and polar fractions are for the most part unknown. This analytical information has been difficult to obtain since these compounds are highly labile, polar, of low volatility and in very low concentrations when compared to the bulk of material found in the SOF. Mutagenicity tests using the Ames Salmonella typhimurium assay indicate that the transition fraction accounts for most of the mutagenicity when compared to the non-polar (PAH) and polar fractions.

A variety of chromatographic and mass spectrometric techniques are described that have been used to determine the composition of the HPLC fractions. More than one hundred species have been identified in the transition fraction of diesel particulate matter using high resolution gas chromatography (HRGC)/high resolution mass spectrometry (HRMS), HPLC and direct-probe high resolution mass spectrometry. It has been found that the transition fraction contains mostly PAH derivatives consisting of hydroxy, ketone, quinone, carboxaldehyde, acid anhydride and dihydroxy derivatives of PAH. Three nitro-PAH species have been tentatively identified and 1-nitropyrene positively identified in the transition fraction. The 1-nitropyrene was found to account for approximately 45% and 30% of the direct-acting mutagenicity observed for the transition fraction and total extract, respectively. The HPLC separation procedure was shown to give better than 95% recovery of the mass and mutagenic activity. The problem of PAH oxidation during the analytical procedures and possible effect on bioassay results are discussed.     

Analytical Determination of Polycyclic Aromatic Hydrocarbons in Gases from Coal Conversion by Synchronous Fluorescence Spectrometry.

Abstract

A method to analyze the most hazardous Polyclyclic Aromatic Hydrocarbons (PAH) (acenaphtene, anthracene, benzo(a) anthracene, benzo(a)pyrene, biphenyl, coronene, chrysene, dibenzo (a,h) anthracene, phenantrene, fluoranthene, fluorene, naphtalene and pyrene), by using excitation and energy constant synchronic fluorescence has been researched in depth in this study.

Spectral studies carried out allow characteristic peaks to be obtained for the qualitative identification of 8 from 11 PAH tested. From the quantitative and interference studies, the most important analytical characteristics (linear range, detection limit and reproduciblity) for the determination of ten of these compounds have been obtained.

The method was applied to the PAH determination in two different samples: 1) air filter samples for urban pollution control and 2) air samples from a laboratory scale coal carbonization oven. Fluorene (in the first type) and benzo (a) pyrene (in the second type), were identified and quantified.     

Chemical Imaging for PAH Analysis in Particulate Materials

Abstract

Chemical imaging is a new analytical science, related to a combination of spatial and chemical resolutions. Several new chemical imaging tools have been developed and applied to environmental analysis. The advantages of such methods, which provide simultaneous morphological/geometrical and chemical speciation, are pointed out and exemplified in several environmental analytical applications. These include fast analysis of PAH contaminated aerosols at low concentrations, analysis of contaminated quartz sand particles, as well as improvement of laser induced fluorescence detection of PAH compounds in natural water, in the presence of various microparticles. It is shown that chemical imaging has a considerable potential in environmental applications and can provide detailed and unique information when particulate materials are concerned.     

Single-stage in situ synthesis of silver nanoparticles in antibacterial self-assembled overlays

In this work, a novel single-stage process for in situ synthesis of Ag nanoparticles (NPs) using the layer-by-layer (LbL) technique is presented. The Ag NPs were formed into nanotextured coatings based on sequentially adsorbed poly(allylamine hydrochloride) (PAH) and SiO₂ NPs. Such highly porous surfaces have been used in the fabrication of highly efficient ion release films for applications such as antibacterial coatings. In this approach, the amino groups of the PAH acted as reducing agent and made possible the in situ formation of the Ag NPs. This reduction reaction occurred during the LbL process as the coating was assembled, without any further step after the fabrication and stabilization of the multilayer film. Biamminesilver nitrate was used as the Ag⁺ ion source during the LbL process and it was successfully reduced to Ag NPs. All coatings were tested with gram-positive and gram-negative bacterial cultures of Escherichia coli, Staphylococcus aureus, and Lactobacillus delbrueckii showing an excellent antimicrobial behavior against these types of bacteria (more than 99.9% of killing efficiency in all cases).     

Analysis of nitrated polycyclic aromatic hydrocarbons by liquid chromatography with fluorescence and mass spectrometry detection: air particulate matter, soot, and reaction product studies

Polycyclic aromatic hydrocarbons (PAH) and their nitrated derivatives (nitro-PAH) are environmental pollutants which pose a threat to human health even at low concentration levels. In this study, efficient analytical methods for the analysis of nitro-PAH and PAH (extraction, clean-up, chromatographic separation, and spectrometric detection) have been developed, characterized, and applied to aerosol samples. The separation and quantification of 12 nitro-PAH was carried out by reversed-phase high performance liquid chromatography (HPLC), on-line reduction, and fluorescence detection. The detection limits were in the range of 0.03–0.5 g L^–1 (6–100 pg in the investigated sample aliquots), and the recovery rates from soot samples were 70–90%. Nitro-PAH and PAH concentrations have been determined for different types of soot and for urban, rural, and alpine fine air particulate matter (PM2.5). For the first time, trace amounts of nitro-PAH have been detected in a high-alpine clean air environment. The on-line reduction and fluorescence technique has been complemented by atmospheric pressure chemical ionization time-of-flight mass spectrometry (APCI-TOF-MS). The MS detection allowed the analysis of partially nitrated and oxygenated PAH in laboratory studies of the heterogeneous reaction of PAH on soot and glass fiber substrates with gaseous nitrogen oxides and ozone. It led to the tentative identification of a previously unknown nitrated derivative of the particularly toxic PAH benzo[a]pyrene (BaP-nitroquinone), and provides the first experimental evidence that PAH-nitroquinones can be formed by reaction of PAH with atmospheric photooxidants.     

Cross‐linked Multilayer Polymer‐Clay Nanocomposites and Permeability Properties

Abstract

Electrostatically layered aluminosilicate nanocomposites have been prepared by the sequential deposition of poly(allylamine hydrochloride)/poly(acrylic acid)/poly(allylamine hydrochloride)/saponite (PAH/PAA/PAH/saponite)₁₀ on poly(ethylene terephtalate) (PET) film. Exfoliated saponite nanoplatelets were obtained by extensive shaking, sonication, and centrifugation of a water suspension. To minimize permeability and improve the mechanical integrity, cross‐linking of composite films was carried out at different temperatures. The formation of amide linkage induced through heating was observed by Fourier Transform Infrared (FT‐IR) and x‐ray photoelectron spectroscopy (XPS). The cross‐linking of nanocomposites (PAH/PAA/PAH/saponite)₁₀ showed 60% decrease in permeability of oxygen when compared with the pristine PET substrate film. In contrast, water permeability of the nanocomposite membrane was not affected by heating temperature and deposition cycles.     

Universal Calibration Method for the Determination of Polycyclic Aromatic Hydrocarbons by High Performance Liquid Chromatography with Broadband Diode-Array Detection

Abstract

The response of polycyclic aromatic hydrocarbons (PAH) at different UV wavelengths was measured using high performance liquid chromatography with spectrophotometric diode-array detection. By utilizing the total UV absorption bandwidth (200-400 nm), it was found that a narrow distribution of normalized response factors (area/g) could be obtained for 16 PAH in a reference mixture of frequently-occurring species, even though the PAH represented a wide variety of different chromophores.

Using the mean response factor for the 16 PAH, a universal calibration factor was obtained that formed the basis of a method for the determination of PAH for which calibration data cannot otherwise be obtained. It utilized normal phase high performance liquid chromatography (HPLC) with a cyanopropyl column and a hexane-dichloromethane mobile phase. The HPLC conditions were optimized for the separation of PAH according to their aromatic ring number. The method was developed for the characterization of complex mixtures of fossil fuels-derived PAH that cannot be analyzed by traditional methods. It is applicable to PAH having from 1 to 10 or more fused aromatic rings.     

A Study On Air Pollution by Asphalt Fumes

Abstract

A TLC/HPLC procedure for the determination of polycyclic aromatic hydrocarbons (PAH), occuring in asphalt fumes (adsorbed on particular matter), is described. The method is based on extraction of asphalt fume particles, collected on glass fibre filters, using CCK₄. Following a clean up step by the aid of a TLC procedure on Al₂ O₃ thinlayer plates, using a mixture of cyclohexane/acetone/ether as the mobile phase. Under UV-light, occuring PAH are indicated as fluorescent spots. A separation of the collected PAH into individual components and their identification is performed by the aid of a HPLC procedure. Futher-more, an approach was made to verify the separated PAH by their fluorescence spectra and their mass spectra.     

Resolution of Polynuclear Aromatic Hydrocarbons by Packed Column GLC

Abstract

Specific GLC stationary phases have been identified which allow the resolution of certain polynuclear aromatic hydrocarbon (PAH) isomers with packed six foot columns. Phenanthrene and benz(a)anthracene can be measured in the PAH fraction of tobacco smoke condensate without significant interferences from anthracene and chrysene, respectively.     

Selective Quenchofluorometric Detection of Fluoranthenic Polycyclic Aromatic Hydrocarbons in High-Performance Liquid Chromatography

Abstract

The phenomenon of fluorescence quenching was used for selective HPLC detection of fluoranthenic polycyclic aromatic hydrocarbons (PAH). Termed a “Quenchofluorometric” detection system, it employs a filter fluorimeter or spectrofluorimeter and nitromethane in the mobile phase as the fluorescence quenching reagent. Chromatograms obtained with and without the quenching reagent are compared for PAH standards, a coal tar extract, and a shale oil sample. The quenchofluorometric detection system provides an inexpensive method to achieve selective detection for fluoranthenic PAH as a group.