Article

A Novel Atmospheric Pressure Photoionization – Mass Spectrometry (APPI-MS) Method for the Detection of Polychlorinated Dibenzo P- Dioxins and Dibenzofuran Homologues in Real Environmental Samples Collected within the Vicinity of Industrial Incinerators

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Abstract

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were monitored in air, soil and vegetation (biota) samples within the vicinity of a solid waste incineration facility located in central Spain. Measurements were made monthly for a one year period. The analyses were carried out using a novel, low flow atmospheric pressure photoionization − mass spectrometry (APPI-MS) method. This technique delivers unique advantages in terms of sensitivity, cost and throughput, with detection limits approaching 1 picogram and an analysis time of 2 minutes. Memory effects were considerable on this first prototype, limiting a final throughput of 4 samples per hour. PCDD and PCDF homologue patterns were observed for each of the air, soil and vegetation samples, and the results obtained were consistent with other studies related to the analysis of incinerator emissions.

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... In contrast, Riddell et al. [44] proposed the use of fluorobenzene, instead of the more toxic toluene, to promote charge-exchange reactions in the ionization of PCDD/Fs in pSFC-APPI positive ion mode. Concerning LC-APCI and LC-APPI negative ion mode, the formation of [M-X + O] À ion occurs by the gas-phase reaction of analyte neutral molecules with superoxide ions, which are generated in these ionization sources even when oxygen is present at trace concentration level [106]. In dopantassisted negative APPI ionization, toluene has been often used for PCBs [3], PCDD/Fs [106] and PCNs [7] yielding the [M-Cl+O] À ion, while for PBDEs [6,24] the best results have been reported using toluene and acetone, which favor the formation of [M-Br+O] À ion for highly brominated PBDEs. ...
... Concerning LC-APCI and LC-APPI negative ion mode, the formation of [M-X + O] À ion occurs by the gas-phase reaction of analyte neutral molecules with superoxide ions, which are generated in these ionization sources even when oxygen is present at trace concentration level [106]. In dopantassisted negative APPI ionization, toluene has been often used for PCBs [3], PCDD/Fs [106] and PCNs [7] yielding the [M-Cl+O] À ion, while for PBDEs [6,24] the best results have been reported using toluene and acetone, which favor the formation of [M-Br+O] À ion for highly brominated PBDEs. In contrast, di-and triBDEs showed a very low response working in negative ion APPI mode [96,108]. ...
... In the case of BDE-209 the ion [C 6 Br 5 O] À was the base peak of the mass spectrum instead of the phenoxide ion observed for other highly brominated BDEs [24,27,109]. Furthermore, when using [M-X+O] À ions as precursor ions in tandem mass spectrometry experiments, they yielded product ions due to losses of chlorine or bromine atoms, providing high selectivity for the corresponding LC-MS/MS methods [3,7,106]. Product ion mass spectra of the [M-Br+O] À precursor ion also yielded a non-specific intense [Br] À ion as reported by Bacaloni et al. for BDE-153 [6]. ...
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Halogenated organic contaminants, including legislated and potential persistent organic pollutants and their precursors, represent a major environmental concern due to their hazardous effects in humans and wildlife as well as their ability to bioaccumulate through the food chain, their high resistance to environmental degradation, and their long-range atmospheric transport potential. The monitoring of these compounds in the environment at ultra-trace concentration levels requires highly selective and sensitive analytical methodologies. The lack of reference step-by-step methods led to a high number of reliable determinations depending on analytes, the complexity of the sample, and available instrumentation. Thus, this review article is mainly focused on the last advances in the analytical methodologies for the determination of halogenated organic contaminants. Methodologies regarding sample treatment, chromatographic separation, and mass spectrometry analysis have been reviewed to finally highlight the future perspectives for the improvement of the analytical determinations of these compounds and the throughput of environmental control laboratories in this field.
... This technique is very useful for non-polar analytes that are difficult to ionize with ESI or APCI such as PAHs, PCDDs, PCDFs, among others. Moreover, some authors reported that with the APPI interface fewer matrix effects were observed than with the other alternative ionization methods mentioned above, such as ESI or APCI [84]. ...
... This is the case of some mass spectrometer systems, where the extracted sample can be infused directly to the ionization source to be subsequently analysed. An example of this is the work carried out by McCulloch et al. [84], who detected polychlorinated dibenzo-p-dioxin and dibenzofuran homologues (PCDDs and PCDFs, respectively) within the vicinity of industrial incinerators. The PM filter was extracted by a Soxhlet extraction with toluene followed by a multi-step cleanup. ...
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The aim of the study was to identify the impact of polychlorinated dibenzo-p-dioxin and furan (PCDD/F) emission sources on ambient air concentrations in the Malopolska Region, southern Poland. Three sites were selected: the city center of Krakow (Aleje), an industrial area (Nova Huta), and a rural site (Zakopane). In order to investigate the annual variations of PCDD/F sources, summer and winter time samples were taken. Ambient air particulate matter (PM10) was collected using an Anderson High-Volume sampler during June and December 2002 in the three mentioned sites. Analysis of PCDD/Fs was based on isotope dilution using high-resolution gas chromatography-high-resolution mass spectrometry for quantification. Total concentrations of 2,3,7,8-PCDD/Fs in air particulate phase from Malopolska region ranged from 0.6 to 37 pg m(-3) (0.04-3.2 pg WHO(98)-TEQ per cubic meter, 0.037-2.9 pg I-TEQ per cubic meter). Higher PCDD/F concentrations were measured at all three sites during winter. A linear correlation among PCDD/F concentrations, benzo(a)pyrene (B(a)P) and PM10 concentrations, was found in Aleje and Zakopane, which suggested that all compounds were originating from the same source, solid fuel domestic heating. Instead, PCDD/F levels in Nova Huta did not correlate with the seasonality of B(a)P or PM10 levels and 2,3,7,8-PCDD/F congener patterns for this site were significantly different from the other sites. Domestic solid fuel combustion is likely the main PCDD/F source in winter in this part of Poland for urban and rural sites. PCDD/F fingerprints in the industrial site remained almost identical during summer and winter, confirming the yearly prevalence of the emissions from the nearby metal industry. PCDD/F concentrations found in Malopolska Region are in the upper range of ambient air concentrations of PCDD/Fs reported worldwide. However, further research is needed in order to study the impact of the deposition of these PCDD/F emissions on the region. A more extended study is being conducted in the area to analyze soil samples, such as sink of atmospheric deposition, and spruce needles, as indicator of PCDD/F availability.
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Polychlorinated dibenzo-p-dioxins (PCDDs) and -furans (PCDFs) are ubiquitous in the environment. This paper estimates the present UK environmental loading of PCDD/Fs in soils, vegetation, air, water and sediments. Greater than 95% of the estimated total PCDD/F loading of 5.7 t in the UK environment is present in surface soils. Annual emissions from known primary sources of PCDDs and PCDFs are estimated. The most important of these include: municipal waste incinerator stack emissions (10.9 kg sigma PCDD/F per annum); industrial (7.7 kg/year) and domestic (5.1 kg/year) combustion of coal; clinical waste incinerators (1.7 kg/year); volatilisation from chlorophenol-treated substrates (1.7 kg/year) and combustion of leaded petrol by motor vehicles (0.7 kg/year). These sources are generally easy to define and reasonably reliable national estimates can be obtained. More difficult to quantify are secondary releases from the large UK stock of pentachlorophenol (PCP) and PCP-treated products, which may represent quantitatively one of the most important sources of total PCDD/Fs to the environment. Estimates of homologue-specific emissions indicate that combustion processes represent a far more significant source of tetra and penta CDD/Fs than do chlorophenols, which in turn constitute a greater source of hepta- and octachlorinated congeners. Direct emission of PCDD/Fs into the atmosphere from combustion processes facilitates their atmospheric transport to remote locations. This, coupled with the diffuse nature of combustion processes, means that the effects of PCDD/F contamination originating from anthropogenic combustion are more widespread than those from the use and disposal of chlorophenols. Contamination from chlorophenols will be more localised, owing to the insignificance of direct atmospheric release pathways for this source. Although there is reasonable agreement between the estimated current annual flux and the present UK environmental loading of PCDDs and PCDFs, a large discrepancy exists between the sum of the annual contributions from primary sources and this annual flux. Whilst the existence of an as yet unidentified source or sources or gross underestimates of known sources cannot be excluded, it is proposed that much of this discrepancy may be accounted for by secondary releases from the use and disposal of chlorophenols and the long-range transport, continued remobilisation and subsequent redeposition of PCDDs and PCDFs already present in the environment. Despite limited evidence for a modest decline in levels of PCDDs and PCDFs in some environmental compartments over the last 20 years, the environmental persistence of these chemicals means that they will remain in the UK environment for the foreseeable future despite recent action to curb primary emissions.
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The results of an assessment study of both industrial and non-industrial dioxin and furan (PCDD/Fs) emissions in the Lombardy Region (Italy) are outlined below. The main data source refer to 1997, and are compiled from the Lombardy Emissions Inventory (developed under the framework of the Regional Air Quality Plan) together with documented emissions factors available. Due to the uncertain nature of the emissions assessment, results are provided as a most probable value within a given range. Total PCDD/Fs emissions in Lombardy average 33 g I-TEQ y(-1), ranging from minimum 13 g I-TEQ y(-1) to maximum 88 g I-TEQ y(-1). The main PCDD/Fs sources are waste incineration, electric arc furnace for steel production, vehicle diesel combustion and residential wood combustion. Incineration emission factors are expected to decrease over the period 2005-2010, in compliance with legal requirements. This will prioritize control over the remaining main PCDD/Fs contributors. Due to limited information available concerning this data, the accuracy of which is uncertain, further research is needed to evaluate the future role of these sources.
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Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were monitored in stack gas and fly ash of various Korean incinerators and in air samples collected near the facilities. Concentrations of PCDD/Fs in emissions were investigated, and characteristic PCDD/F homologue patterns were classified using statistical analyses. The PCDD/F emission levels in stack gas and fly ash samples from small incinerators (SIs) were higher than those from municipal solid waste incinerators (MSWIs). The PCDD/F concentrations ranged between 0.38 and 1.16 pg I-TEQ/m3 (21.2-75.2 pg/m3) in ambient air samples. The lower-chlorinated furans were the dominant components in most of the stack gas and fly ash samples from SIs, although this was not the case for fly ash from MSWIs. This homologue pattern is consistent with other studies reporting a high fraction of lower-chlorinated furans in most environmental samples affected by incinerator emissions, and it can be used as an indicator to assess the impact of such facilities on the surrounding environment.
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Matrix effects on mass spectrometry (MS) response were investigated with three atmospheric pressure ionization (API) sources after on-line solid-phase extraction (SPE) of human plasma. On-line SPE was evaluated with one restricted access material (RAM), two large particle supports (LPS) and one monolith. A sample protein precipitation (PP) with acetonitrile (2:1) and a direct injection were tested. Principal component analysis (PCA) was performed to simplify data presentation and interpretation. Protein precipitation was found to be mandatory for reducing signal modification. Regarding sensitivity towards matrix effects after PP, atmospheric pressure photoionization (APPI) was globally the least sensitive ionization mode while electrospray ionization ESI was the most sensitive.
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During the development of a method for quantitative determination of venlafaxine and its major metabolite O-desmethylvenlafaxine, elevated concentrations of the analyte as well as co-eluting matrix compounds caused ion suppression. This ion suppression was inconsistent and therefore influenced the reproducibility of detection. The use of atmospheric pressure photoionization (APPI) in the positive mode was investigated as a tool to circumvent this problem. Employing APPI resulted in negligible ion suppression and increased linearity of the concentration range. A selective, sensitive and rapid liquid chromatography/tandem mass spectrometry method for the determination of venlafaxine and its major metabolite O-desmethylvenlafaxine in human plasma was developed. The analyte was extracted from plasma into tert-butyl methyl ether followed by back extraction into 2% formic acid. An Agilent 1100 high-performance liquid chromatography (HPLC) system, employing reversed-phase chromatography on a cyano column, coupled to an Applied Biosystems API 3000 triple quadrupole mass spectrometer set to multiple reaction monitoring (MRM) mode, was used for separation and detection of the analytes. The method was validated between 2.36-605 ng per mL with a mean recovery of approximately 88% for both parent compound and metabolite analytes. APPI technology was employed to improve the reproducibility of detection enabling rapid, selective and sensitive quantification of venlafaxine and O-desmethylvenlafaxine in human plasma samples.
Article
Gas chromatography (GC) and ion trap mass spectrometry (MS) were combined with microchip atmospheric pressure chemical ionization (microAPCI) and microchip atmospheric pressure photoionization (microAPPI) sources. Selected polychlorinated biphenyls (PCBs, IUPAC Nos. 28, 52, 101, 118, 138, 153 and 180) were analyzed by GC/microAPCI-MS and GC/microAPPI-MS to demonstrate the applicability of the miniaturized ion sources in negative ion mode analysis. The microAPCI and microAPPI methods were evaluated in respect of detection limit, linearity and repeatability. The detection limits for the PCB congeners were somewhat lower with microAPCI than with microAPPI, whereas microAPPI showed slightly wider linear range and better repeatability. With both methods, the best results were obtained for highly chlorinated or non-ortho-chlorinated PCBs, which possess the highest electron affinities. Finally, the suitability of the GC/microAPPI-MS method for the analysis of PCBs in environmental samples was demonstrated by analyzing soil extracts, and by comparing the results with those obtained by gas chromatography with electron capture detection (GC/ECD).