Analysis Of Polycyclic Aromatic Compounds Research Articles

Determination of policyclic aromatic compounds, (PAH, nitro-PAH and oxy-PAH) in soot collected from a diesel engine operating with different fuels

A qualitative and quantitative analysis of polycyclic aromatic compounds (PACs; polycyclic aromatic hydrocarbons (PAHs), oxygenated and nitrated polycyclic aromatic hydrocarbons (OPAHs and NPAHs)) present in the soluble organic fraction (SOF) of different soot samples has been carried out to determine the effect of soot-generation conditions on their composition and health effects. The soot samples were generated using a diesel engine bench powered by diesel (DS) and biodiesel (BS) fuels under different combustion conditions. To optimize the procedure, a surrogate soot (Printex-U) and a certified reference material (SRM1650b) were also tested. Different extraction methods were used to extract the PAHs, OPAHs and NPAHs, and the Soxhlet technique using pyridine:acetic acid 1 % was found to be the most suitable procedure to extract the highest concentration (ng mg−1) and more types of PAHs and OPAHs from the soot. The results show that the PACs identified, and their concentrations, depend on the formation and collection conditions. The predominant compounds in all soot samples studied were fluorene (Flo), phenanthrene (Phe), fluoranthene (Fla), pyrene (Pyr), 9-fluorenone (9Flo) and 9,10-anthraquinone (9,10Anq). As such, the presence of these PACs in the atmosphere of urban and rural areas can mainly be attributed to the emissions from diesel vehicles. The percentage of OPAHs with respect to total PACs was highest in the soot generated from a biofuel. These oxidized compounds favor regeneration of the diesel particulate filter (DPF). The results also indicate that the carcinogenicity of the soot depends on the combustion conditions and type of fuel.

Quantitative Structure-Retention Relationship Analysis of Polycyclic Aromatic Compounds in Ultra-High Performance Chromatography.

A comparative quantitative structure-retention relationship (QSRR) study was carried out to predict the retention time of polycyclic aromatic hydrocarbons (PAHs) using molecular descriptors. The molecular descriptors were generated by the software Dragon and employed to build QSRR models. The effect of chromatographic parameters, such as flow rate, temperature, and gradient time, was also considered. An artificial neural network (ANN) and Partial Least Squares Regression (PLS-R) were used to investigate the correlation between the retention time, taken as the response, and the predictors. Six descriptors were selected by the genetic algorithm for the development of the ANN model: the molecular weight (MW); ring descriptor types nCIR and nR10; radial distribution functions RDF090u and RDF030m; and the 3D-MoRSE descriptor Mor07u. The most significant descriptors in the PLS-R model were MW, RDF110u, Mor20u, Mor26u, and Mor30u; edge adjacency indice SM09_AEA (dm); 3D matrix-based descriptor SpPosA_RG; and the GETAWAY descriptor H7u. The built models were used to predict the retention of three analytes not included in the calibration set. Taking into account the statistical parameter RMSE for the prediction set (0.433 and 0.077 for the PLS-R and ANN models, respectively), the study confirmed that QSRR models, associated with chromatographic parameters, are better described by nonlinear methods.

Extensive chemical and bioassay analysis of polycyclic aromatic compounds in a creosote-contaminated superfund soil following steam enhanced extraction

Polycyclic aromatic compounds (PACs) are organic compounds commonly found in contaminated soil. Previous studies have shown the removal of polycyclic aromatic hydrocarbons (PAHs) in creosote-contaminated soils during steam enhanced extraction (SEE). However, less is known about the removal of alkyl-PAHs and heterocyclic compounds, such as azaarenes, and oxygen- and sulfur-heterocyclic PACs (OPACs and PASHs, respectively). Further, the impact of SEE on the freely dissolved concentration of PACs in soil as well as the soil bioactivity pre- and post-SEE have yet to be addressed. To fulfil these research gaps, chemical and bioanalytical analysis of a creosote-contaminated soil, collected from a U.S. Superfund site, pre- and post-SEE were performed. The decrease of 64 PACs (5–100%) and increase in the concentrations of nine oxygenated-PAHs (OPAHs) (150%) during SEE, some of which are known to be toxic and can potentially contaminate ground water, were observed. The freely dissolved concentrations of PACs in soil were assessed using polyoxymethylene (POM) strips and the concentrations of 66 PACs decreased post-SEE (1–100%). Three in vitro reporter gene bioassays (DR-CALUX®, ERα-CALUX® and anti-AR CALUX®) were used to measure soil bioactivities pre- and post-SEE and all reporter gene bioassays measured soil bioactivity decreases post-SEE. Mass defect suspect screening tentatively identified 27 unique isomers of azaarenes and OPAC in the soil. As a remediation technique, SEE was found to remove alkyl-PAHs and heterocyclic PACs, reduce the concentrations of freely dissolved PACs, and decrease soil bioactivities.

Handle Matrix Rank Deficiency, Noise, and Interferences in 3D Emission-Excitation Matrices: Effective Truncated Singular-Value Decomposition in Chemometrics Applied to the Analysis of Polycyclic Aromatic Compounds.

The characterization of organic compounds in polluted matrices by eco-friendly three-dimensional (3D) fluorescence spectroscopy coupled with chemometric algorithms constitutes a powerful alternative to the separation techniques conventionally used. However, the systematic presence of Rayleigh and Raman scattering signals in the excitation–emission matrices (EEMs) complicates the spectral decomposition via PARAllel FACtor analysis (PARAFAC) due to the nontrilinear structure of these signals. Likewise, the specific problem of selectivity in spectroscopy for unexpected chemical components in a complex sample may render its chemical interpretation difficult at first glance. The relevant chemical information can then be complicated to extract, especially if the raw data is noisy. There are several strategies to overcome these drawbacks, but weaknesses remain. As a consequence, a new alternative method is proposed to handle these interferences, the noise, and the rank deficiencies in the data and applied for the characterization of polycyclic aromatic compound (PAC) mixtures. It is based on effective truncated singular-value decomposition (MT-SVD) that does not require any prior knowledge of the raw data. The algorithm provides a valuable estimation of the global rank to choose on complex samples where selectivity problems are observed. It is a real alternative compared to other existing methods applied to the fluorescence matrix to filter the signal from noise or light scattering effects. The first exploratory results of the proposed algorithm are promising to handle matrix rank deficiencies as well as the effects of noise and light scattering on complex PAC mixtures.

The use of pseudo-MRM for a sensitive and selective detection and quantification of polycyclic aromatic compounds by tandem mass spectrometry.

Multiple Reaction Monitoring (MRM) is a sensitive and selective detection mode for target trace-level analysis. However, it requires the fragmentation of labile bonds which are not present in molecules such as Polycyclic Aromatic Hydrocarbons (PAHs) and their heterocyclic derivatives (PANHs, PASHs). We present the application of an alternative tandem mass spectrometry (MS/MS) mode called "pseudo-MRM" for the GCMS/MS analysis of Polycyclic Aromatic Compounds (PACs). This mode is based on the monitoring of transitions with no mass loss between the precursor and the product ion. Pseudo-MRM peak areas were compared with those of classic MRM on three different mass spectrometers: two triple quadrupoles and an ion trap. For all non-polar PACs studied here (PAHs, PANHs and PASHs), the pseudo-MRM transition was always the most intense. The classic MRM transitions exhibited peak areas 2 to 5 times lower. On the contrary, for the functionalized PACs (oxygenated and nitrated PAHs), classic MRM was favored over pseudo-MRM. These observations were confirmed on two triple quadrupoles (QqQs), and the real-world applicability of pseudo-MRM on QqQs was validated by the successful analysis of Diesel PM. However, a comparison with an ion trap showed that pseudo-MRM was never favored on that instrument, which caused fragmentation of non-polar PACs in MS/MS. The results of this study show an important gain in sensitivity when using pseudo-MRM instead of MRM for non-polar PACs on QqQ instruments. The selectivity of MRM is preserved in pseudo-MRM by applying non-zero collision energies to which only these non-polar PACs are resistant, not the isobaric interferences. No interference issue was observed when analyzing Diesel PM, a complex matrix, with our pseudo-MRM method. Therefore, we advise for a broader use of this MS/MS mode for trace-level determination of non-polar PAHs.

Hierarchically Synthesis of Nanoflower Layered Double Hydroxide/Molybdenum Disulfide on Electrochemically Anodized HB Pencil Lead for Determination Trace Amounts of Polycyclic Aromatic Hydrocarbons

Preparation coating materials is a fundamental point in solid-phase microextraction (SPME) fiber fabrications. So, a hydrothermal approach was developed for fabricating 3 D hierarchically molybdenum disulfide/layered double hydroxide on anodized HB pencil lead, Nanosheets of a porous molybdenum disulfide and layered double hydroxide were directionally arranged on anodized HB pencil lead and used as a fiber coating for selectively analysis of polycyclic aromatic compounds (PAHs) by headspace SPME method. The as-synthesized materials were characterized by thermal gravimetric analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, According to the results, this coating indicated considerable potential due to extracting trace amounts of some carcinogenic polycyclic aromatic compounds in water samples. The essential parameters such as extraction time, extraction temperature, agitation speed, and ionic strength of sample that mainly affect the adsorption process were optimized and in optimum values, the repeatabilities for one fiber were between 4.6% and 9.1% for the test compounds were achieved. The studied compounds were assessed within the detection limits as follows: 0.028 to 0.42 ngL−1.

Integrated analysis of petroleum biomarkers and polycyclic aromatic compounds in lake sediment cores from an oil sands region.

We examined polycyclic aromatic compounds (PACs) and petroleum biomarkers (steranes, hopanes, and terpanes) in radiometrically-dated lake sediment cores from the Athabasca oil sands region (AOSR) and the Peace-Athabasca Delta (PAD) region in Alberta (Canada) to determine whether contributions from petroleum hydrocarbons have changed over time. Two floodplain lakes in the PAD (PAD 30, PAD 31) recorded increased flux of alkylated PACs and increased petrogenic (petroleum-derived) hydrocarbons after ∼1980, coincident with a decline of sediment organic carbon content and a rise of bulk sedimentation rate, likely due to increased Athabasca River flow. A large expansion of upstream oilsands mining, upgrading, and refining may also have contributed to the observed shift to more petrogenic hydrocarbons to sediments since the 1980s. Alkylated PAC flux increased in the floodplain lake analyzed within the AOSR (Saline Lake) since the 1970s-1980s, coincident with a sharp rise in sediment organic carbon content and increased contributions of petrogenic hydrocarbons. These changes identify increased supply of petrogenic PACs occurred as Athabasca River floodwaters waned, and may implicate aerial contributions of petrogenic hydrocarbons from oilsands activity. PACs and petroleum biomarkers (steranes, hopanes, and terpanes) in sediment cores from Saline Lake, PAD 30 and PAD 31 revealed a predominance of petrogenic hydrocarbons in these lakes. In contrast, we recorded minimal petrogenic hydrocarbons in the reference lakes outside the surface minable area of the AOSR and PAD (Mariana Lake and BM11), though we noted slight increases in petrogenic contributions to modern (2010-2016) sediments. We show how a combined analysis of PACs and petroleum biomarkers in sediments is useful to quantify petrogenic contributions to lakes with added confidence and highlight the potential for petroleum biomarkers in lake sediment cores as a novel and effective method to track petroleum hydrocarbons in lake sediment.

Co-exposures to trace elements and polycyclic aromatic compounds (PACs) impacts North American river otter (Lontra canadensis) baculum

Environmental loadings of polycyclic aromatic compounds (PACs) and trace elements are increasing in areas with marked oil and gas extraction, such as in the Athabasca oil sands region, Alberta, Canada. Some of these chemicals are recognized as potent endocrine disrupting compounds (EDCs). The impacts of co-exposure to PACs and metals on free-ranging wildlife is of considerable concern. River otters (Lontra canadensis) are sentinel species of aquatic ecosystem health. The baculum (penile bone) is an important part of the reproductive system in otters that ensures successful copulation. Although baculum health is critical to male reproductive success and is sensitive to exposure to EDCs, there is no information available regarding the impact of PAC and metal exposures on measures of baculum health. River otter baculum and livers were dissected from carcasses obtained from the fur trade. Trace element and PAC analyses were carried out in liver with matching baculums subjected to dimensional analysis, bone mineral density (BMD) and mechanical loading testing. Trace elements and select PACs exhibited both protective and deleterious effects on baculum bone health metrics. Alkylated four ring PACs were negatively associated with baculum bone material properties (ex: C4-Chrysene and C4-pyrene). The same compounds have been shown to exhibit strong anti-androgenic activities. Few comparable studies exist related to contamination and adverse effects of PACs in wild terrestrial mammals. Baculum health metrics may be an important tool to include in biomonitoring studies as to date, there are limited means to assess male reproductive performance in wildlife biomonitoring programs.

Quantitative biomonitoring of polycyclic aromatic compounds (PACs) using the Sydney rock oyster (Saccostrea glomerata)

Increasing our understanding of the bioavailable fractions of polycyclic aromatic compounds (PACs) in an aquatic environment is important for the assessment of the environmental and human health risks posed by PACs. More importantly, the behaviour of polar polycyclic aromatic hydrocarbons (polar PAHs), which are metabolites of legacy PAHs, are yet to be understood. We, therefore, carried out a study involving Sydney rock oysters (Saccostrea glomerata) sourced from two locations, that had been exposed to PAH contamination, within an Australian south-east estuary. Biomonitoring of these oysters, following relocation from the estuary to a relatively isolated waterway, was done at 24 and 72 h after deployment and subsequently at 7, 14, 28, 52 and 86 days. Control samples from Camden Haven River were sampled for PAC analyses just before deployment, after 28 days and at the end of the study (day 86). Lipid-normalised concentrations in oyster tissues across the 86-day sampling duration, elimination rate constants (k2), biological half-lives (t1/2) and time required to reach 95% of steady-state (t95) were reported for parent PAHs and the less-monitored polar PAHs including nitrated/oxygenated/heterocyclic PAHs (NPAHs, oxyPAHs and HPAHs) for the three differently sourced oyster types. Most of the depurating PAHs and NPAHs, as well as 9-FLO (oxyPAH), had k2 values significantly different from zero (p < 0.05). All other oxyPAHs and HPAHs showed no clear depuration, with their concentrations remaining similar. The non-depuration of polar PAHs from oyster tissues could imply greater human health risk compared to their parent analogues.

Extraction of polycyclic aromatic compounds (PAC) and the influence on the mechanical and chemical properties of asphalt binder

As a part of Aromatics fraction in asphalt binder, polycyclic aromatic compounds (PAC) is chemical group, including some different kinds of several thousand individual compounds, which have a negative impact on the environment and human health. PAC in asphalt binder is potentially hazardous due to volatile components and leakages; therefore measurements and analyses of PAC in asphalt binder are recommended. The common method of separating asphalt binders is impractical for the analysis of PAC, thus an innovative method is proposed. Four binders are studied with their short-term and long-term aged samples. Based on the measurement of the PAC and asphaltenes contents, effects of various aging processes on the components of PAC are investigated in this paper. Furthermore, the influence of PAC on the mechanical and chemical properties of binders is studied. The results show that the PAC exhibit significant differences before and after ageing processes. Compared with the asphaltenes compound, PAC has an opposing effect on the mechanical properties of asphalt binders. On the other hand, the chemical properties of PAC is studied to explore the mechanism of the softening effect. In addition, four binary functions with PAC and asphaltenes contents are established in this study.

Optimization of a large-volume injection method for compound-specific isotope analysis of polycyclic aromatic compounds at trace concentrations.

Compound-specific isotope analysis (CSIA) of persistent organic contaminants can be used for source apportioning in the environment if appropriate sensitivity can be achieved. This paper describes the optimization and validation of a sensitive analytical approach for the determination of the carbon isotope composition of semi-volatile organic compounds, such as polycyclic aromatic hydrocarbons (PAHs). Analyses are based on the introduction of up to 150 μL of organic extracts by means of programmed temperature vaporization-large-volume injection combined with gas chromatography coupled to isotope ratio mass spectrometry (PTV-LVI-GC/IRMS). To allow for the analysis of more volatile, low-molecular-weight PAHs, the PTV injector was equipped with a sub-ambient/cryogenic cooling. Accuracy, precision, linearity and determination limits for application in isotope analysis were evaluated for a set of individual PAHs ranging from two- to five-ring molecular structures. The method was exemplified by determining the δ(13) C values of individual PAHs in soil samples in a source apportionment study at a contaminated site. The choice of PTV injection parameters is crucial to prevent isotope fractionation during injection and largely depends on the analytes to be determined. The observed isotope fractionation effect on semi-volatiles depends on the applied solvent and injection temperature and demonstrates the importance of performing appropriate tests with given PTV parameters for each of the compounds of interest. The proposed PTV-LVI-GC/IRMS method allows the carbon isotope ratio (δ(13) C value) of individual PAHs to be determined accurately and precisely at concentrations of 0.04-0.1 ng μL(-1) even for volatile PAHs such as naphthalene or acenaphthene. LVI with PTV injector cooling allows for the isotopic analysis of volatile and semi-volatile PAHs at trace concentrations, thus considerably expanding the applicability of CSIA in environmental studies.

Comparison of different exhaustive and biomimetic extraction techniques for chemical and biological analysis of polycyclic aromatic compounds in river sediments

Purpose The importance of the bioaccessible fractions of particle-bound contaminants is a key feature for the assessment of their likely risks to the aquatic environment. The present study investigated the extractability and potential toxicity of polycyclic aromatic hydrocarbons (PAHs) in river sediments. This study combined chemical with bioanalytical tools to establish a more in-depth insight into the relationship between the extractability of sediment contaminants, the chemodynamic properties of each extraction approach, and resulting toxicity.

Comparison of ultrasonic and pressurized liquid extraction for the analysis of polycyclic aromatic compounds in soil samples by gas chromatography coupled to tandem mass spectrometry

A pressurized liquid extraction (PLE) method has been optimized for the determination of polycyclic aromatic hydrocarbons (PAHs) in soil samples and it was compared with ultrasonic extraction. The extraction step was followed by gas chromatography–triple quadrupole mass spectrometry (GC–QqQ-MS/MS) analysis. Parameters such as type of solvent, extraction time, extraction temperature and number of extractions were optimized. There were no significant differences among the two extraction methods although better extraction efficiencies were obtained when PLE was used, minimizing extraction time and solvent consumption. PLE procedure was validated, obtaining limits of detection (LODs) ranging from 0.02 to 0.75 μg kg −1 and limits of quantification (LOQs) ranging from 0.07 to 2.50 μg kg −1 for the selected PAHs. Recoveries were in the range of 59–110%, except for naphthalene, which was the most volatile PAH. Finally, the method was applied to real soil samples from Southeast of Spain. PAHs concentrations were low, and phenanthrene, pyrene, fluorene, benzo[ a]pyrene and chrysene were the most frequently detected analytes in the samples.

Challenges and progress in the analysis of polycyclic aromatic compounds

Challenges and progress in the analysis of polycyclic aromatic compounds

The importance of both charge exchange and proton transfer in the analysis of polycyclic aromatic compounds using atmospheric pressure chemical ionization mass spectrometry

The response of atmospheric pressure chemical ionization (APCI) mass spectrometry to selected polycyclic aromatic compounds (PACs) was examined in a Micromass Quattro atmospheric pressure ion source as a function of both solvents and source gases. Typical PACs found in petroleum samples were represented by mixtures of naphthalene, fluorene, phenanthrene, pyrene, fluoranthene, chrysene, triphenylene, perylene, carbazole, dibenzothiophene, and 9-phenanthrol. A large range of different gases in the APCI source was studied, with emphasis on nitrogen, air, and carbon dioxide. Solvents used included water-acetonitrile, acetonitrile, dichloromethane, and hexanes. The signal responses were dependent on both the gases and solvents used, as was the ionization mechanism, as indicated by the degree of protonation with respect to the level of charge exchange. The combination of carbon dioxide in the nebulizer gas stream with nitrogen in the other streams gave a three- to fourfold better sensitivity than using nitrogen alone for both test mixtures and for complex samples.

Analysis of Polycyclic Aromatic Compounds Using Microbore Columns

The gas chromatographic analysis of polycyclic aromatic compounds can be completed faster and with increased chromatographic resolution using microbore columns (Fast GC). Microbore columns contain two to three times the number of theoretical plates per meter when compared to 0.25 mm internal diameter (i.d.) capillary columns. The increased chromatographic resolving power of microbore columns enables separations to be carried out with much shorter columns giving rise to faster analysis times. Analysis times of priority polycyclic aromatic hydrocarbons on 20 m (5% phenyl, 0.1 mm i.d., 0.1 w m film thickness) and 10 m (5% phenyl, 0.1 mm i.d., 0.1 w m film thickness) columns are reduced by about 45% and 60% respectively in comparison with 30 m columns, and data quality (precision and accuracy) is not affected. All areas/parameters of the chromatographic system must be adjusted and optimized to ensure proper chromatographic performance. Smaller injection volumes (0.2-0.5 w L) and injection liners (1-2 mm i.d.) are required to obtain optimum (and reproducible) chromatography on 0.1 mm i.d. columns.

Analysis of Polycyclic Aromatic Compounds Using Microbore Columns

The gas chromatographic analysis of polycyclic aromatic compounds can be completed faster and with increased chromatographic resolution using microbore columns (Fast GC). Microbore columns contain two to three times the number of theoretical plates per meter when compared to 0.25 mm internal diameter (i.d.) capillary columns. The increased chromatographic resolving power of microbore columns enables separations to be carried out with much shorter columns giving rise to faster analysis times. Analysis times of priority polycyclic aromatic hydrocarbons on 20 m (5% phenyl, 0.1 mm i.d., 0.1 w m film thickness) and 10 m (5% phenyl, 0.1 mm i.d., 0.1 w m film thickness) columns are reduced by about 45% and 60% respectively in comparison with 30 m columns, and data quality (precision and accuracy) is not affected. All areas/parameters of the chromatographic system must be adjusted and optimized to ensure proper chromatographic performance. Smaller injection volumes (0.2-0.5 w L) and injection liners (1-2 mm i.d.) are required to obtain optimum (and reproducible) chromatography on 0.1 mm i.d. columns.

Determination of Polycyclic Aromatic Compounds in Asphalt and in Corresponding Leachate Water

The environmental impact of polycyclic aromatic compounds (PACs) in asphalt (bitumen) materials is related to their availability for environmental transport and biouptake, rather than their total concentrations. This study examines six Strategic Highway Research Program (SHRP) paving asphalts and four commercial roofing asphalts. Three cleanup procedures for the neat asphalt samples are evaluated. This study reports on analyses for 29 PACs, including the EPA 16 priority pollutant PAHs and additional Persistent Bioaccumulative Toxins. These require reporting by the U.S. EPA under the Emergency Planning and Community Right-to-Know Act (EPCRA) section 313. The analytical protocol for analysis of the higher molecular weight PACs by GC/MS is reported, with inclusion of GC/MS/MS verification of some of the detectable compounds. Additionally, each asphalt was taken through a toxicity characteristic leaching procedure following U.S. EPA method SW846-1311. Results of the paving and roofing asphalts and their corresponding leachate waters are presented in this study.

Determination of Polycyclic Aromatic Compounds in Asphalt and in Corresponding Leachate Water

The environmental impact of polycyclic aromatic compounds (PACs) in asphalt (bitumen) materials is related to their availability for environmental transport and biouptake, rather than their total concentrations. This study examines six Strategic Highway Research Program (SHRP) paving asphalts and four commercial roofing asphalts. Three cleanup procedures for the neat asphalt samples are evaluated. This study reports on analyses for 29 PACs, including the EPA 16 priority pollutant PAHs and additional Persistent Bioaccumulative Toxins. These require reporting by the U.S. EPA under the Emergency Planning and Community Right-to-Know Act (EPCRA) section 313. The analytical protocol for analysis of the higher molecular weight PACs by GC/MS is reported, with inclusion of GC/MS/MS verification of some of the detectable compounds. Additionally, each asphalt was taken through a toxicity characteristic leaching procedure following U.S. EPA method SW846-1311. Results of the paving and roofing asphalts and their corresponding leachate waters are presented in this study.

Window target-testing factor analysis: theory and application to the chromatographic analysis of complex mixtures with multiwavelength fluorescence detection

Window target-testing factor analysis (WTTFA) is a new data analysis method that can help confirm the presence or absence of an analyte in a severely overlapped chromatogram. It is intended to be used in chromatographic applications with multichannel detection and is based on principal component analysis. The algorithm attempts to determine if the response profile of a target analyte lies within the response subspace of a time window containing unresolved chromatographic peaks. Because the window moves sequentially through the chromatogram, WTTFA allows a relative assessment of match quality. To test the new method, a procedure for simulating complex chromatograms has been developed. The simulated data allow the limitations of WTTFA to be tested under different conditions of chromatographic complexity, spectral overlap, measurement noise, window size and other factors. As a practical demonstration of its utility, the method is applied to the chromatographic analysis of polycyclic aromatic compounds in a complex petroleum distillate using multiwavelength fluorescence detection. WTTFA indicates the presence of 1-methylpyrene in an unresolved cluster of peaks. This is confirmed through a combination of mass spectrometry, heart-cut chromatography and self-modeling curve resolution.