A suite of analytical tools was applied to thoroughly analyze the chemical composition of an oil/gas well flowback water from the Denver-Julesburg (DJ) basin in Colorado, and the water quality data ...was translated to propose effective treatment solutions tailored to specific reuse goals. Analysis included bulk quality parameters, trace organic and inorganic constituents, and organic matter characterization. The flowback sample contained salts (TDS=22,500 mg/L), metals (e.g., iron at 81.4 mg/L) and high concentration of dissolved organic matter (DOC=590 mgC/L). The organic matter comprised fracturing fluid additives such as surfactants (e.g., linear alkyl ethoxylates) and high levels of acetic acid (an additives' degradation product), indicating the anthropogenic impact on this wastewater. Based on the water quality results and preliminary treatability tests, the removal of suspended solids and iron by aeration/precipitation (and/or filtration) followed by disinfection was identified as appropriate for flowback recycling in future fracturing operations. In addition to these treatments, a biological treatment (to remove dissolved organic matter) followed by reverse osmosis desalination was determined to be necessary to attain water quality standards appropriate for other water reuse options (e.g., crop irrigation). The study provides a framework for evaluating site-specific hydraulic fracturing wastewaters, proposing a suite of analytical methods for characterization, and a process for guiding the choice of a tailored treatment approach.
► Exact masses and fragment ions of 100 pharmaceuticals by LC/Q-TOF-MS. ► Use of resolving power for discrimination of isobaric/isomeric compounds. ► Fragmentation patterns shown for some ...pharmaceuticals by accurate mass. ► Relevant environmental findings after analysis of surface water samples.
A straightforward methodology for the chromatographic separation and accurate mass identification of 100 pharmaceuticals including some of their degradation products was developed using liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/Q-TOF-MS). A table compiling the protonated or deprotonated exact masses for all compounds, as well as the exact mass of several fragment ions obtained by MS–MS is included. Excellent chromatographic separation was achieved by using 3.5μm particle size columns and a slow and generic 30-min gradient. Isobaric and isomeric compounds (same nominal mass and same exact mass, respectively) were distinguished by various methods, including chromatography separation, MS–MS fragmentation, and isotopic signal identification. Method reporting limits of detection ranged from 1 to 1000ng/L, after solid-phase extraction of 100mL aqueous samples. The methodology was successfully applied to the analysis of surface water impacted by wastewater effluent by identifying many of the pharmaceuticals and metabolites included in the list. Examples are given for some of the most unusual findings in environmental samples. This paper is meant to serve as a guide for those doing analysis of pharmaceuticals in environmental samples, by providing exact mass measurements of several well known, as well as newly identified and environmentally relevant pharmaceuticals in water samples.
A quantitative methodology using high resolution mass spectrometry was developed for the identification of organic compounds derived from wildfires in surface water samples. The methodology involves ...the use of solid-phase extraction (SPE) followed by detection using liquid chromatography-quadrupole time of flight-mass spectrometry (LC/Q-TOF-MS) for a group of fourteen chemical compounds (pyridine, benzene, naphthalene and biphenyl polycarboxylic acids). All compounds were successfully separated chromatographically using a reversed phase column and they were identified by accurate mass using the deprotonated species and their main fragment ions. The method produced excellent accuracies (>95%) and precisions (3–10%) for all the compounds studied. This methodology was successfully applied to the identification of fourteen compounds in runoff surface waters impacted by wildfires in Colorado in 2020. Concentrations of individual compounds ranging from 0.1 to 59.5 μg/L were found in wildfire impacted waters, with totals of ∼200 μg/L, thus showing these compounds as chemical tracers of wildfire events at significantly high concentrations. In addition, non-target analysis using chromatography patterns and mass spectrometry identification by MS-MS revealed other polycarboxylic acid isomers were also present in runoff surface water samples.
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•Quantitative methodology for 14 organic acids in wildfire-impacted surface waters.•Compounds found in surface waters are chemical tracers for wildfires.•Concentrations in runoff surface (blackwaters) varied from 0.1 to 59.5 μg/L.•Non-target analyses revealed a new set of naphthalene carboxylic acid isomers.
The chemical additives used in fracturing fluids can be used as tracers of water contamination caused by hydraulic fracturing operations. For this purpose, a complete chemical characterization is ...necessary using advanced analytical techniques. Liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC/Q-TOF-MS) was used to identify chemical additives present in flowback and produced waters. Accurate mass measurements of main ions and fragments were used to characterize the major components of fracking fluids. Sodium adducts turned out to be the main molecular adduct ions detected for some additives due to oxygen-rich structures. Among the classes of chemical components analyzed by mass spectrometry include gels (guar gum), biocides (glutaraldehyde and alkyl dimethyl benzyl ammonium chloride), and surfactants (cocamidopropyl dimethylamines, cocamidopropyl hydroxysultaines, and cocamidopropyl derivatives). The capabilities of accurate mass and MS-MS fragmentation are explored for the unequivocal identification of these compounds. A special emphasis is given to the mass spectrometry elucidation approaches used to identify a major class of hydraulic fracturing compounds, surfactants.
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•Discovery of two new surfactant groups in wastewater from hydraulic fracturing.•One surfactant is polypropylene glycol including isomers.•The other surfactant is carboxylated ...polyethylene glycol.•A downloadable database for fingerprinting flowback water was designed.•The surfactants may be less toxic than their monomers.
The purpose of the study was to separate and identify the unknown surfactants present in flowback and produced water from oil and gas wells in the Denver-Julesburg Basin (Niobrara Formation) in Weld County, Colorado, USA. Weld County has been drilled extensively during the last five years for oil and gas between 7000–8000 feet below land-surface. Polypropylene glycols (PPGs) and polyethylene glycols carboxylates (PEG-Cs) were found for the first time in these flowback and produced water samples. These ethoxylated surfactants may be used as friction reducers, clay stabilizers, and surfactants. Ultrahigh-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UHPLC/QTOF-MS) was used to separate and identify the different classes of PPGs, PEG-Cs, and their isomers. The Kendrick mass scale was applied along with mass spectrometry/mass spectrometry (MS-MS) with accurate mass for rapid and unequivocal identification. The PPGs and their isomers occur at the ppm concentration range and may be useful as “fingerprints” of hydraulic-fracturing. Comparing these detections to the compounds used in the fracturing process from FracFocus 3.0 (https://fracfocus.org), it appears that both PPGs and polyethylene glycols (PEGs) are commonly named as additives, but the PEG-Cs have not been reported. The PEG-Cs may be trace impurities or degradation products of PEGs.
Two series of ethylene oxide (EO) surfactants, polyethylene glycols (PEGs from EO3 to EO33) and linear alkyl ethoxylates (LAEs C-9 to C-15 with EO3–EO28), were identified in hydraulic fracturing ...flowback and produced water using a new application of the Kendrick mass defect and liquid chromatography/quadrupole-time-of-flight mass spectrometry. The Kendrick mass defect differentiates the proton, ammonium, and sodium adducts in both singly and doubly charged forms. A structural model of adduct formation is presented, and binding constants are calculated, which is based on a spherical cagelike conformation, where the central cation (NH4 + or Na+) is coordinated with ether oxygens. A major purpose of the study was the identification of the ethylene oxide (EO) surfactants and the construction of a database with accurate masses and retention times in order to unravel the mass spectral complexity of surfactant mixtures used in hydraulic fracturing fluids. For example, over 500 accurate mass assignments are made in a few seconds of computer time, which then is used as a fingerprint chromatogram of the water samples. This technique is applied to a series of flowback and produced water samples to illustrate the usefulness of ethoxylate “fingerprinting”, in a first application to monitor water quality that results from fluids used in hydraulic fracturing.
A methodology for the chromatographic separation and analysis of three of the most popular artificial sweeteners (aspartame, saccharin, and sucralose) in water and beverage samples was developed ...using liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS). The sweeteners were extracted from water samples using solid-phase extraction (SPE) cartridges. Furthermore, several beverages were analyzed by a rapid and simple method without SPE, and the presence of the sweeteners was confirmed by accurate mass measurements below 2-ppm error. The unambiguous confirmation of the compounds was based on accurate mass measurements of the protonated molecules M+H
+, their sodium adducts and their main fragment ions. Quantitation was carried out using matrix-matched standard calibration and linearity of response over 2 orders of magnitude was demonstrated (
r
>
0.99). A detailed fragmentation study for sucralose was carried out by time-of-flight and a characteristic spectrum fingerprint pattern was obtained for the presence of this compound in water samples. Finally, the analysis of several wastewater, surface water and groundwater samples from the US showed that sucralose can be found in the aquatic environment at concentrations up to 2.4
μg/L, thus providing a good indication of wastewater input from beverage sources.
Opioids, both as prescription drugs and abuse substances, have been a hot topic and a focus of discussion in the media for the last few years. Although the literature published shows the occurrence ...of opioids and some of their metabolites in the aquatic environment, there are scarce data in the application of high resolution mass spectrometry (HRMS) for the analysis of these compounds in the environment. The use of HRMS allows increasing the number of opioids that can be studied as well as the detection of unknown opioids, their metabolites and potential transformation products. In this work, a retrospective analysis for the identification of opioids and their metabolites using a curated database was applied to surface water and wastewater samples taken in the state of Minnesota (U.S.) in 2009, which were previously analyzed by liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS) for antidepressants. The database comprised >200 opioids including natural opiates (e.g. morphine and codeine), their semi-synthetic derivatives (e.g. heroin, hydromorphone, hydrocodone, oxycodone, oxymorphone, meperidine and buprenorphine), fully synthetic opioids (e.g. fentanyl, methadone, tramadol, dextromethorphan and propoxyphene), as well as some of their metabolites (e.g. 6-monoacetylcodeine, dextrorphan, EDDP, normorphine and O-desmethyltramadol). Moreover, additional MS-MS experiments were performed to confirm their identification, as well as to recognize fragmentation patterns and diagnostic ions for several opioids. These data provide a better understanding of the historical occurrence of opioids and their metabolites in surface waters impacted by wastewater sources. The concentrations of individual opioids in surface water and wastewater effluent varied from 8.8 (EDDP) to 1640 (tramadol) ngL−1 and from 12 (dihydrocodeine) to 1288 (tramadol) ngL−1, respectively. The opioids with higher overall frequency detections were tramadol, dextromethorphan and its metabolite, dextrorphan.
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•An accurate mass database for >200 opioids and their metabolites was developed.•Retrospective data analysis was carried out for the identification of opioids and their metabolites.•Historical opioid occurrence in surface water samples from Minnesota was obtained and discussed.•A detailed MS-MS study for several opioids and their metabolites by HRMS is presented.•The most frequently detected opioids in samples were dextromethorphan, dextrorphan and tramadol.
To provide the first nationwide reconnaissance of the occurrence of pharmaceuticals, hormones, and other organic wastewater contaminants (OWCs) in water resources, the U.S. Geological Survey used ...five newly developed analytical methods to measure concentrations of 95 OWCs in water samples from a network of 139 streams across 30 states during 1999 and 2000. The selection of sampling sites was biased toward streams susceptible to contamination (i.e. downstream of intense urbanization and livestock production). OWCs were prevalent during this study, being found in 80% of the streams sampled. The compounds detected represent a wide range of residential, industrial, and agricultural origins and uses with 82 of the 95 OWCs being found during this study. The most frequently detected compounds were coprostanol (fecal steroid), cholesterol (plant and animal steroid), N,N-diethyltoluamide (insect repellant), caffeine (stimulant), triclosan (antimicrobial disinfectant), tri(2-chloroethyl)phosphate (fire retardant), and 4-nonylphenol (nonionic detergent metabolite). Measured concentrations for this study were generally low and rarely exceeded drinking-water guidelines, drinking-water health advisories, or aquatic-life criteria. Many compounds, however, do not have such guidelines established. The detection of multiple OWCs was common for this study, with a median of seven and as many as 38 OWCs being found in a given water sample. Little is known about the potential interactive effects (such as synergistic or antagonistic toxicity) that may occur from complex mixtures of OWCs in the environment. In addition, results of this study demonstrate the importance of obtaining data on metabolites to fully understand not only the fate and transport of OWCs in the hydrologic system but also their ultimate overall effect on human health and the environment.
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