Improvements in the determination of chlorobenzenes and chlorophenols through a stepwise interlaboratory study approach

A systematic quality control programme carried out by a number of laboratories from the European Union and from EFTA countries is described. The programme was designated to improve the analytical state of the art in the determination of selected chlorinated benzenes and chlorinated phenols in different environmental matrices. To that end a stepwise interlaboratory study approach was chosen, analysing, in consecutive order, a clean extract of soil, a raw extract and the soil itself. Eight analytes were selected for the study, i.e. three chlorobenzenes and five chlorophenols. During the programme significant improvements in analytical performance were achieved, as shown by a decrease in within-laboratory coeffficients of variation as well as by acceptable coefficients of variation in the mean value of laboratory means of all analytes in the final matrix analysed, i.e. a natural soil. The results of the programme prompted the European Union to embark upon a pentachlorophenol interlaboratory certification study to produce an industrial soil candidate Certified Reference Material (CRM) [1]. Received: 28 August 1997 / Revised: 15 October 1997 / Accepted: 21 October 1997     

Improvements in the determination of chlorobenzenes and chlorophenols through a stepwise interlaboratory study approach

A systematic quality control programme carried out by a number of laboratories from the European Union and from EFTA countries is described. The programme was designated to improve the analytical state of the art in the determination of selected chlorinated benzenes and chlorinated phenols in different environmental matrices. To that end a stepwise interlaboratory study approach was chosen, analysing, in consecutive order, a clean extract of soil, a raw extract and the soil itself. Eight analytes were selected for the study, i.e. three chlorobenzenes and five chlorophenols. During the programme significant improvements in analytical performance were achieved, as shown by a decrease in within-laboratory coeffficients of variation as well as by acceptable coefficients of variation in the mean value of laboratory means of all analytes in the final matrix analysed, i.e. a natural soil. The results of the programme prompted the European Union to embark upon a pentachlorophenol interlaboratory certification study to produce an industrial soil candidate Certified Reference Material (CRM) [1].     

Simplified determination of polycyclic aromatic hydrocarbons

Accurate quantitative analysis for selected polycyclic aromatic hydrocarbons present on urban dust can be obtained by using a simple procedure consisting of sonic-probe extraction with cyclohexane; clean-up with Florisil((R))-XAD-4((R)), and measurement by high-resolution gas chromatography with flame-ionization detection (HRGC/FID). The analysis can be further simplified by eliminating the clean-up step if HRGC/electron-impact mass-spectrometry (MS) is available. Both the FID and MS methods give results consistent with those obtained by standard procedures. The direct HRGC/MS procedure, combined with chemical ionization, can also be applied to the determination of polycyclic organic materials present in solvent-refined coal, shale oil and crude oil.     

The spectrophotometric determination of polycyclic aromatic hydrocarbons

The determination of polycyclic aromatic hydrocarbons by elution chromatography from alumina columns followed by ultra-violet spectrophotometry has been elaborated for a more extended range of substances than has been published previously. The methods have been standardised and tables of absorption peaks are provided for easy identification of a number of compounds commonly found as traces in combustion products. Recommendations are given for the preparation of samples for determinations by this method, which has been successfully employed for the analysis of carbon blacks, soots, urban air solids, condensible smokes such as tobacco smoke, wood smoke and coal tar. thermal decomposition or pyrolysis products and other substances, such as urban vegetation, soil, tobacco, snuff, smoked food, and surface drainage water, which have been subjected to the action of smokes or other combustion products.     

A convergent approach to polycyclic aromatic hydrocarbons

A new concise route to Polycyclic Aromatic Hydrocarbons (PAHs) through radical addition and cyclisation of xanthates is described.     

Adsorption preconcentration in the luminescence determination of polycyclic aromatic hydrocarbons

The adsorption of polycyclic aromatic hydrocarbons (PAHs)—pyrene, anthracene, phenanthrene, and fluorene—by a cellulose matrix of micellar media containing sodium dodecyl sulfate and a nonionogenic polymer, namely, polyethylene glycol is studied. Procedures are proposed for the luminescence determination of PAHs in the adsorbent phase.     

Chromatographic determination of polycyclic aromatic hydrocarbons in oil sludge

It has been demonstrated that the Oasis HLB polymer adsorbent can be used for the purification of hexane extracts of oil sludge for the determination of polycyclic aromatic hydrocarbons by high-performance liquid chromatography with a fluorometric detector in these samples. The determination of polycyclic aromatic hydrocarbons has been carried out in samples of different wastes.     

Standard reference materials for the determination of polycyclic aromatic hydrocarbons

Summary Since 1980 a number of Standard Reference Materials (SRM's) have been issued by the National Bureau of Standards (NBS) to assist in validating measurements for the determination of polycyclic aromatic hydrocarbons (PAH) and other polycyclic aromatic compounds (PAC). These SRM's are certified for selected PAC and range in analytical difficulty from calibration solutions to complex natural matrix materials, such as air and diesel particulate matter, shale oil, and crude oil. In the past year three new SRM's have been introduced: (1) SRM 1647a Priority Pollutant PAH in Acetonitrile, (2) SRM 1491 Aromatic Hydrocarbons in Hexane/Toluene, and SRM 1597 Complex Mixture of PAH from Coal Tar. The SRM's available from NBS for use in the determination of PAC are described and the concentrations of PAC determined in the natural matrix SRM's are summarized and compared. The primary analytical techniques used for the measurement of PAC in these SRM's were gas chromatography, liquid chromatography, and gas chromatography/mass spectrometry.

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Standardreferenzmaterialien für die Bestimmung von polycyclischen aromatischen Kohlenwasserstoffen

     

Differential calorimetric study of polycyclic aromatic hydrocarbons

The temperature, enthalpy, entropy of melting and crystal transitions of 21 polycyclic aromatic hydrocarbons, containing from 2 to 6 unsubstituted condensed rings, were determined by differential scanning calorimetry. The temperature and the molar entropy of melting generally increase with increasing degree of symmetry and molecular size of the hydrocarbon. Apparent deviations from this trend are discussed in terms of molecular distorsion due to steric interaction between neighbouring hydrogens.     

Method validation for determination of the 15 European-priority polycyclic aromatic hydrocarbons in primary smoke condensates by gas chromatography/mass spectrometry: interlaboratory study

A collaborative study was conducted to validate an analytical method for quantification of the 15 polycyclic aromatic hydrocarbons (PAHs) regarded in 2002 as a health concern by the former Scientific Committee on Food of the European Commission (SCF) in primary smoke condensates. The method is based on gas chromatography/mass spectrometry of a cyclohexane extract with solid-phase cleanup through silica gel. The analytes were detected in the selected-ion monitoring mode and quantified by using 3 isotopically labeled internal standard compounds. Seventeen laboratories participated in the collaborative validation study, of which 12 reported valid results. The data were subjected to Cochran, single Grubbs, and double Grubbs tests for statistical outliers. A maximum of 2 outliers was eliminated before further statistical evaluation of the method performance characteristics. Depending on the analyte, the results showed relative standard deviations for repeatability between 4.2 and 30% and for reproducibility from 9.9 to 60%. The recoveries varied between about 50 and 85%, except those for cyclopenta[cd]pyrene, dibenzo[a,l]pyrene, and dibenzo[a,h]pyrene. Nevertheless, because Commission Directive 2005/10/EC allows for a recovery range of 50-120% for (BaP) benzo[a]pyrene in various foods, it can be concluded that the method performs appropriately within the analytical range between 5 and 25 microg/kg of primary smoke condensate. For BaP the validated analytical range covered 5-20 microg/kg, and for benzo[a]anthracene (BaA) 10-25 microg/kg. The method is suitable for monitoring BaP and BaA at their respective maximum permitted levels of 10 and 20 microg/kg. Three analytes, benzo[b]-, benzo[j]-, and benzo[k]-fluoranthene could not be separated by all of the participants and were therefore treated as the sum. Nevertheless, with this method the pattern of the respective concentrations of these 15 PAHs can be monitored in primary smoke condensate as suggested by the SCF.     

The spectrophotometric determination of polycyclic aromatic hydrocarbons. II

In repetitive determinations of polycyclic aromatic hydrocarbons in combustion products the use of incompletely separated Chromatographic fractions is often an advantage favouring rapid work. Such fractions may be submitted to an approximate quantitative analysis by using tables of absorption peak heights measured from a base-line drawn between theminima on each side of the peak. Convenient tables for this method are provided in this paper.     

Method for determination of polycyclic aromatic hydrocarbons by fluorodensitometry

A TLC fluorodensitometric method for the determination of total PAHs in aqueous and hydroalcoholic solutions at the parts per billion level has been developed. The PAHs are extracted into cyclohexane and separated as a class on a chemically bonded reversed-phase TLC plate using stepwise development. In the fluorescence scanning of the plate the PAHs are located by reference to a mixture of 16 PAHs designated by EPA as primary pollutants and measured as benzo(a)pyrene.     

自来水中七种多环芳烃的快速测定

多环芳烃（PAH）在环境中分布广、浓度低，空气、土壤和水的样品中均能检出。PAH大都含有致癌和促进致癌的物质及变异性成分。世界卫生组织拟定了饮用水中六种有代表性多环芳烃总的最高可接受浓度为200ng／L。     

Direct arylation of polycyclic aromatic hydrocarbons through palladium catalysis

We have discovered that the combination of Pd(OAc)(2)/o-chloranil can catalyze the direct C-H bond arylation of polycyclic aromatic hydrocarbons (PAHs) with arylboroxins that occurs selectively at the K-region. The sequential integration of Pd-catalyzed direct arylation of PAHs and FeCl(3)-mediated cyclodehydrogenation is effective in rapidly extending a parent PAH π-system with high directionality.     

New approach for screening polycyclic aromatic hydrocarbons in water samples

For the first time, solid-phase extraction (SPE) has been combined to room-temperature phosphorimetry (RTP) to determine the 16 polycylic aromatic hydrocarbons related as major pollutants by the US Environmental Protection Agency (EPA). These include naphthalene, anthracene, acenaphthylene, acenaphthene, fluorene, fluoranthene, benzo(a)anthracene, benzo(k)fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, pyrene, chrysene, phenanthrene, benzo(g,h,i)perylene and dibenzo(a,h)anthracene. The pre-concentration factor obtained by SPE, combined with the sensitivity of RTP, resulted in calibration curves with linear dynamic ranges at the parts-per-billion level (ng ml(-1)). The limits of detection were estimated at the parts-per-trillion level (pg ml(-1)). Several pollutants usually encountered in water samples were tested for interference. These included polychlorinated biphenyls, pesticides, and volatile organic compounds. As a result of the appropriate combination of excitation wavelength (330 nm) and phosphorescence enhancers (0.1 M TlNO(3) and 0.05 M sodium dodecyl sulfate, SDS), no interference was observed. The results demonstrate the potential of SPE-RTP for screening polycyclic aromatic hydrocarbons (PAHs) in environmental waters.     

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).     

Shpol''skii fluorimetric determination of polycyclic aromatic hydrocarbons in complex environmental samples

Summary High-resolution fluorimetry in low-temperature n-alkane Shpol'skii matrices is a powerful technique for the analysis of rigid, non-polar compounds like polycyclic aromatic hydrocarbons. Because of the method's sensitivity and selectivity, sample clean-up, preconcentration and even chromatographic separation can often be left out. The Shpol'skii analysis of pyrene in crude extracts from marine sediments and from bird meat is demonstrated. Special attention is focussed on the extra possibilities acquired when a laser is used as excitation source (Laser Excited Shpol'skii Spectroscopy, LESS).