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An oil spill is a catastrophic event that results in various toxic polycyclic aromatic hydrocarbons (PAHs) entering the environment. Polycyclic aromatic nitrogen heterocycles (PANHs) are more toxic to the environment than their parent PAHs. The high cost and paucity of available PANH standards, the lower abundance of PANHs relative to PAHs, and the difficult separation due to co-elution with PAHs have all contributed to the scarcity of related published literature on the determination of these compounds. To overcome these challenges, a new quantitative method has been successfully developed and validated for the inclusion of 113 polycyclic aromatic carbon (PAC) compounds in a single injection. The 113 compounds consist of PAHs, nitrogen heterocycles, sulfur heterocycles, and alkylated equivalents. Distinct separation of the PANHs and their alkylated counterparts (APANHs) from PAHs was achieved using a gas chromatography quadrupole time-of-flight (GC-QToF) mass spectrometer. The instrument resolved compounds by the high-resolution extraction of monoisotopic masses, allowing response correction factors (RCFs) to be determined from available PANH standards and to calculate concentrations from PAH calibration standards. The developed method was applicable to crude oil samples, generating concentrations of PANHs and relevant information on compound stability for use in oil spill forensics investigation. Development of this practical PAC method provides a powerful tool for screening toxic contaminants, assessing environmental impact, and monitoring recovery following an oil spill. [ABSTRACT FROM AUTHOR]

Background: Oil spills are widespread and can cause devastating environmental consequences. Rapid oil identification is critical to find the origin of the spill, monitor the environment, and lead to informed mitigation measures. The current standard methods in oil spill identification are precise and reliable, but require extensive sample preparation, long instrument runs, and time-consuming data processing. Direct analysis in real time time-of-flight mass spectrometry (DART-ToF MS) has been employed to screen for spilled petroleum oils, with results obtained in mere hours. The present study introduced an innovative, simple, and fast oil sampling method using hydrophobic filter paper and demonstrated its compatibility with DART-ToF MS analysis. Motor oils, jet fuels, marine diesels, crude oils, intermediate fuel oils, heavy fuel oils, and diluted bitumen were collected using the filter paper sampling method. Classification models were constructed from the spectral data by heat map inspection followed by principal component analysis (PCA) and discriminant analysis of principal components (DAPC). Oil slicks and weathered oil slicks were prepared from five oil types, and samples from each slick were collected using filter paper. Results: The filter paper technique allowed for effective oil sampling and data acquisition by DART-ToF MS for diluted source oils, oil slicks and weathered oil slicks. Classification via the constructed DAPC models indicated that the DART-ToF MS instrument in tandem with filter paper sampling and multivariate statistics can accurately identify common oil types, with significant improvement of sample collection and turnaround time. Conclusions: The promising classification results, simple sample collection, and rapid data analysis illustrate the potential use of hydrophobic filter paper and DART-ToF MS as tools in managing large scale oil spill emergency situations. [ABSTRACT FROM AUTHOR]

Background: The biomarker diagnostic ratio analysis outlined by the European Committee for Standardization is considered the current gold standard in oil forensic analysis. However, it has a major limitation as an emergency response procedure in the case of a large scale oil spill due to the high number of samples collected, long GC/MS instrument run time, and the time-consuming data processing required. This current study utilized direct analysis in real time time-of-flight mass spectrometry to develop a rapid spilled oil screening method. An exploratory search of biomarkers and synthetic additives was conducted on reference oil samples of various types. To build a robust yet swift procedure for oil typing, specific heat maps were built with extensive reference sample modelling. These heat maps were then used to select relevant ions from which principal component analysis and discriminant analysis of principal component models were constructed to result in defensible oil classifications. Results: The initial exploratory search of biomarkers and additives in the various reference oil samples resulted in promising preliminary matches. The heat map and multivariate statistical analysis oil typing method was applied to three unknown samples, all of which were classified accurately. Conclusion: The merit of direct analysis in real time time-of-flight mass spectrometry on oil forensic was confirmed with the detected biomarkers compound class starting members and lubricating additives along with the successful application of heat maps and multivariate statistical analysis, providing a swift yet reliable screening tool for oil spill environmental monitoring and impact surveying. [ABSTRACT FROM AUTHOR]

Current oil spill forensic identification of source oils relies upon hydrocarbon biomarkers resistant to weathering. This international technique was developed by the European Committee for Standardization (CEN), under EN 15522–2 Oil Spill Identification guidelines. The number of biomarkers have expanded at pace with technological advances, while distinguishing new biomarkers becomes more challenging due to interference of isobaric compounds, matrix effects, and high cost of weathering experiments. Application of high-resolution mass spectrometry enabled exploration of potential polycyclic aromatic nitrogen heterocycle (PANH) oil biomarkers. The instrumentation showed reduction in isobaric and matrix interferences, allowing for identification of low-level PANH and alkylated PANHs (APANHs). Weathered oil samples, obtained from a marine microcosm weathering experiment, enabled comparison with source oils to identify new, stable forensic biomarkers. This study highlighted eight new APANH diagnostic ratios that expanded the biomarker suite, increasing the confidence for identifying highly weathered oils back to their source oil. [ABSTRACT FROM AUTHOR]

Oil spill forensic investigations are often challenging due to many confounding variables such as sample weathering, oil composition complexities, and the quality or quantity of collected materials, but the difficulty is further compounded when dealing with mixed oils. In this case, well-established oil fingerprinting techniques become inadequate, including gas chromatography-flame ionization detection (GC/FID) and gas chromatography-mass spectrometry (GC/MS) diagnostic ratio analysis. In dealing with mixtures of highly refined lubricating (lube) oils, GC/FID analysis often yields inconclusive results, while diagnostic ratio analysis can be compromised by missing or low response biomarker compounds. The present study explored the feasibility of addressing the challenges of mixed lube oil analysis through a multi-tiered analytical approach. This analysis supplemented traditional GC/FID and GC/MS diagnostic ratio analyses with multivariate statistics to rapidly screen large data sets. Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) proved to be effective and intuitive qualitative methods for visualizing, differentiating, and characterizing four highly similar lube oil mixtures. Non-linear mixing patterns that were significant in the diagnostic ratio analysis were far less evident through LDA. Overall, these findings lay the groundwork for promising future study involving multivariate statistical approaches to complex mixed oil forensic cases. [ABSTRACT FROM AUTHOR]

One of the common toxic compound groups in crude oils are the polycyclic aromatic sulfur heterocycles (PASHs) and their related alkylated forms (APASHs). Unlike commonly investigated polycyclic aromatic hydrocarbons (PAHs) and their alkylated forms (APAHs), these sulfur containing compounds have not been extensively studied due to the lack of practical analytical methodology as well as expense and limited availability of chemical standards. In the current study, a newly developed polycyclic aromatic carbon (PAC) method was applied to analyze the various PASHs/APASHs in crude oil samples using PAHs as surrogate standards. To investigate the fate of PASHs/APASHs in spilled oils in the environment, microcosm systems containing various crude oils were prepared and exposed to the environment for two months, simulating the summer weather conditions of Canada's west coast. The artificially weathered crude oil samples were analyzed for both PAH/APAH and PASH/APASH composition, and the results were compared to un-weathered counterparts of the oils. PASHs/APASHs were found to be affected by the microcosm weathering in similar ways to PAHs/APAHs. Fifteen PASHs and APASHs were found to be resistant to weathering and be potential candidates as biomarkers in oil spill forensic investigation. [ABSTRACT FROM AUTHOR]

Observations made for the analysis of the oil spill dispersant tracer dioctyl sulfosuccinate (DOSS) during LC50 toxicity testing, highlighted a stability issue for this tracer compound in seawater. A liquid chromatography high-resolution quadrupole time-of-flight mass spectrometry (LC/QToF) was used to confirm monooctyl sulfosuccinate (MOSS) as the only significant DOSS breakdown product, and not the related isomer, 4-(2-ethylhexyl) 2-sulfobutanedioate. Combined analysis of DOSS and MOSS was shown to be applicable to monitoring of spill dispersants Corexit® EC9500A, Finasol OSR52, Slickgone NS, and Slickgone EW. The unassisted conversion of DOSS to MOSS occurred in all four oil spill dispersants solubilized in seawater, although differences were noted in the rate of MOSS formation. A marine microcosm study of Corexit EC9500A, the formulation most rapid to form MOSS, provided further evidence of the stoichiometric conversion of DOSS to MOSS under conditions relevant to real world dilbit spill. Results supported combined DOSS and MOSS analysis for the monitoring of spill dispersant in a marine environment, with a significant extension of sample collection time by 10 days or longer in cooler conditions. Implications of the unassisted formation of MOSS and combined DOSS:MOSS analysis are discussed in relation to improving dispersant LC50 toxicity studies. [ABSTRACT FROM AUTHOR]

A saponification extraction method with gas chromatography pseudo-MRM (pMRM) mass spectrometry detection was developed for the determination of 50 total polycyclic aromatic hydrocarbons (TPAH50, a combination of parent and alkylated homologues) in biota. The method was aimed at monitoring and identification of potential TPAH contaminants in bitumen impacted environments. Alkylated PAHs were determined by multi-level, quantitative calibration using parent PAHs. The developed and thoroughly validated method required only one injection for TPAH50 analysis which represents significant saving of time and expensive authentic alkylated standards. The current method was tested with certified reference mussel tissue NIST 1974c and performed well. In a comparison study, the method reached a limit of quantitation (LOQ) for the TPAH50 between 0.1 and 0.2 ng g−1, while the QuEChERs enhanced matrix removal – lipid (EMR) kit produced by Agilent showed an LOQ of 5–10 ng g−1. The current method relied on response factors (RF) for the quantitation of alkylated PAHs determined against parent PAHs. These RFs were shown to be stable and consistent over the course of 1 year, during which over 200 routine environmental biota monitoring samples were analyzed. The environmental biota monitoring samples analyzed include muscle, carcass and liver, with an average total PAH50 concentration of 13, 90 and 135 ng g−1, respectively. Results show significant differences in the distributions of 1 ringed, 2 ringed, 3 ringed, 4 ringed, and 5+ ringed TPAHs between the types of biota samples. [ABSTRACT FROM AUTHOR]

Time-driven and event-driven control models are two fundamental design paradigms applied in distributed control systems for synchronizing decentralized activities. This paper proposes a unified architecture for combining both approaches. The combination offers the best of both worlds’ properties, such as the expressiveness of event-driven programming and the determinism of time-driven logic. The foundations of this symbiosis are the IEC 61499 Function Block standard providing event-driven distributed control architecture and the IEEE 1588 Precision Time Protocol establishing the basis for highly-accurate time synchronization. The proposed time-complemented event-driven distributed control model aims at improving the modularity and flexibility of automation software with satisfactory control performance. The new control model has been compared with conventional centralized and distributed control approaches analytically and by simulation. The comparison results reveal that the proposed control model is efficient and flexible. Finally, a reference example has been used to demonstrate merits of the new approach. [ABSTRACT FROM AUTHOR]

This paper presents a novel model-driven software architecture for systems with high degree of redundancy and modularity of the equipment. The architecture is based on totally decentralized control. It combines adaptability and robustness of multi-agent control architectures with portability and interoperability benefits of IEC 61499 function block architecture. The architecture has been successfully proven feasible on a number of field trials, including modeling and implementation of a medium-scale airport baggage handling control. Deployment was done on distributed networks consisting of configurations ranging from a few to dozens of communicating control nodes. The work confirmed the ability to deliver similar functional characteristics as centralized systems but in a distributed implementation. Performance testing and development verified sufficient performance and software life-cycle benefits. [ABSTRACT FROM PUBLISHER]