Ian Brindle - Academia.edu (original) (raw)

Papers by Ian Brindle

Journal of the American Society for Mass Spectrometry, Nov 1, 1993

Spectrochimica Acta Part B: Atomic Spectroscopy, May 1, 1996

Analyst, 2005

Static headspace sampling technique coupled with gas chromatography and mass spectrometry was use... more Static headspace sampling technique coupled with gas chromatography and mass spectrometry was used to investigate the presence of volatile 2-alkyl-3-methoxypyrazines in three different species of ladybugs of the Coccinellidae family. The species investigated were Coccinella septempunctata, Harmonia axyridis and Hippodemia convergens. 2-isopropyl-3-methoxypyrazine (IPMP) was identified in all three species with detectable levels of 2-sec-butyl-3-methoxypyrazine (SBMP) and 3-isobutyl-2-methoxypyrazines (IBMP) in only Hippodemia convergens and Harmonia axyridis species. Relative amounts of 2-alkyl-3-methoxypyrazines based on body mass showed that Hippodemia convergens had the highest levels of all three methoxypyrazines and Coccinella septempunctata the least.

American Journal of Enology and Viticulture, 2004

Chemischer Informationsdienst, Apr 22, 1980

Investigations into the use of experimental membranes (Empore), containing iminodiacetate residue... more Investigations into the use of experimental membranes (Empore), containing iminodiacetate residues, as well as Millipore SEP PAK cartridges, containing either acid or basic alumina, have been carried out at the Ontario Ministry of Environmental and Energy laboratories in Rexdale, Ontario. In this paper, we report the results of our investigations by ICP mass spectrometry of recoveries of metal ions from drinking and surface waters.

Journal of the American Chemical Society, 2006

Talanta, Feb 1, 2016

Focused infrared radiation-based digestions, for the determination of gold and silver, can be ach... more Focused infrared radiation-based digestions, for the determination of gold and silver, can be achieved in a timeframe as short as 10-15min, making it an attractive candidate technology for the mining industry, where very large numbers of samples are analyzed on a daily basis. An investigation was carried out into gold and silver dissolution chemistry from geological samples using this novel digestion technique. This study investigated in-depth the issue of low recoveries of gold from aqua regia (AR) digestions, reported by a number of researchers. Conventional AR digestions consistently delivered gold recoveries in a range of 69-80% of the certified values for the four certified reference materials (CRM) employed (CCU-1d, SN26, OREAS 62c, and AMiS 0274), while silver recoveries were satisfactory. By gradually shifting the HCl:HNO3 ratio (v/v) from 3:1 to a reversed 1:3 ratio, recoveries of gold and silver exhibited inverse trends. At a HCl:HNO3 ratio of 1:3, complete recovery of gold was achieved with excellent reproducibility in all CRMs. Meanwhile, silver recoveries plunged significantly at this ratio in samples with higher silver concentrations. Silver values were recovered, however, when the silver was re-solubilized by adding a small volume of concentrated HCl to the cooled reverse aqua regia digests. Recoveries of base metals, such as Fe and Cu, were satisfactory throughout and were much less sensitive to changes in the digestion medium. Using four CRMs and five real-world gold/silver containing samples, the utility of the proposed reverse aqua regia was systematically studied. The uncomplicated nature of the digestion methods reported here, that are fast, effective and inexpensive, may be useful to analysts developing/optimizing their methods for the rapid determination of Au and Ag in a variety of mineral phases, particularly where rapid results are desirable, such as in prospecting and mine development.

Analytical and Bioanalytical Chemistry, Dec 2, 2009

Until recently, atmospheric pressure photoionization (APPI) has typically been used for the deter... more Until recently, atmospheric pressure photoionization (APPI) has typically been used for the determination of non-polar halogenated flame retardants (HFRs) by liquid chromatography (LC) tandem mass spectrometry. In this study, we demonstrated the feasibility of utilizing liquid chromatography atmospheric pressure chemical ionization (APCI) tandem mass spectrometry (LC-APCI-MS/MS) for analysis of 38 HFRs. This developed method offered three advantages: simplicity, rapidity, and high sensitivity. Compared with APPI, APCI does not require a UV lamp and a dopant reagent to assist atmospheric pressure ionization. All the isomers and the isobaric compounds were well resolved within 14-min LC separation time. Excellent instrument detection limits (6.1 pg on average with 2.0 μL injection) were observed. The APCI mechanism was also investigated. The method developed has been applied to the screening of wastewater samples for screening purpose, with concentrations determined by LC-APCI-MS/MS agreeing with data obtained via gas chromatography high resolution mass spectrometry. Keywords Atmospheric pressure chemical ionization (APCI). Liquid chromatography tandem mass spectrometry (LC-MS/MS). Halogenated flame retardants (HFRs). Wastewater

Rapid Communications in Mass Spectrometry, Jan 7, 2011

Although the two flame retardants 1,2‐dibromo‐4‐(1,2‐dibromoethyl)cyclohexane (TBECH) and 1,2,5,6... more Although the two flame retardants 1,2‐dibromo‐4‐(1,2‐dibromoethyl)cyclohexane (TBECH) and 1,2,5,6‐tetrabromocyclooctane (TBCO) have been widely used, a selective instrumental method of analysis for these compounds has not been developed to date. In this study, we demonstrate the feasibility to utilize liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the separation and analysis of α‐ and β‐TBCO and α‐, β‐, γ‐, and δ‐TBECH. Acetone was initially used in a tetrahedron solvent system for LC optimization. A simple isocratic elution allowed near‐baseline separation of these compounds. Different ionization approaches and mechanisms were investigated. The mass spectrometric transition of [M + O2]– => Br– (459.8 => 78.9) was a selective detection method for the target analytes. Good instrument detection limits (5 pg for γ‐/δ‐TBECH, 125 pg for α‐/β‐TBECH, and 30 pg for α‐/β‐TBCO with 2.0 µL injection) were obtained. Excellent linearity up to 50 ng/µL (R2 >0.999) was also achieved. This method has been applied to environmental samples (surface water) for screening purposes with recoveries ranging from 76–92% (CV%: 5–8%). This method shows significant improvement over previous methods. Copyright © 2011 John Wiley & Sons, Ltd.

Rapid Communications in Mass Spectrometry, Jan 7, 2011

In this work, we evaluate the performance of liquid chromatography-atmospheric pressure photoioni... more In this work, we evaluate the performance of liquid chromatography-atmospheric pressure photoionization-mass spectrometry (LC-APPI-MS) for non-aqueous reversed phase analysis of six triacylglycerol model compounds using six binary mobile phases including MeOH/iPrOH, MeOH/CHCl 3 , MeOH/CH 2 Cl 2 , CH 3 CN/iPrOH, CH 3 CN/CHCl 3 , and CH 3 CN/CH 2 Cl 2. All mobile phases give comparably good separation performance on a Gemini C 18 column with carefully adjusted gradient elution programs. APPI sensitivity varies from one mobile phase to the other without dopants; however use of dopants brings sensitivity to comparable levels for all mobile phases. MeOH/iPrOH offers high sensitivity without dopants due to self-doping effect and dopants are not necessary for this mobile phase. Dopants enhance analyte sensitivity to a varying degree for each of the mobile phases tested. Photo-induced chemical ionization (PCI) of solvent may play a significant role in achieving high sensitivity. Two critical parameters affecting sensitivity are photoabsorption cross-sections and ionization potentials of mobile phase solvents. How these mobile phase solvents affect APPI sensitivity and their dependency on dopant use are discussed. All six mobile phases offer comparable overall limits of detection for the analytes tested. These results indicate that LC-APPI-MS is a successful tool for neutral lipid analysis, giving high sensitivity with a variety of non-aqueous mobile phases.

Environmental Pollution, Nov 1, 2008

This study determines spatial trends and congener patterns of 2378-substituted polychlorinated di... more This study determines spatial trends and congener patterns of 2378-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in surficial sediments of Lakes Erie and Ontario. Sediments are enriched in 2378-PCDFs in Lake Ontario, and the PCDD/F concentrations increased from shallow near-shore sediments towards deep-water depositional zone sediments. In Lake Erie, sediments were dominated by octachlorodibenzo-p-dioxin, and the highest PCDD/F concentrations were observed in the western basin and the southern shoreline of the central basin with a decrease towards the eastern basin and the northern shoreline of the central basin. Principal components analysis revealed that chemical manufacture and disposal of chemical waste along the Niagara River has been a major PCDD/F source to Lake Ontario; while PCDD/Fs in Lake Erie are from multiple sources including industrial sources along the Detroit River, major tributaries along the southern shoreline of the lake, and atmospherically-derived material from the upper lakes and connecting channels.

HAL (Le Centre pour la Communication Scientifique Directe), Jun 8, 2007

Talanta, 2016

Short-wavelength infrared radiation has been successfully applied to accelerate the acid digestio... more Short-wavelength infrared radiation has been successfully applied to accelerate the acid digestion of refractory rare-earth ore samples. Determinations were achieved with microwave plasma-atomic emission spectrometry (MP-AES) and dynamic reaction cellinductively coupled plasma-mass spectrometry (DRC-ICP-MS). The digestion method developed was able to tackle high iron-oxide and silicate matrices using only phosphoric acid in a time frame of only 8 min, and did not require perchloric or hydrofluoric acid. Additionally, excellent recoveries and reproducibilities of the rare earth elements, as well as uranium and thorium, were achieved. Digestions of the certified reference materials OREAS-465 and REE-1, with radically different mineralogies, delivered results that mirror those obtained by fusion processes. For the rare-earth CRM OKA-2, whose REE data are provisional, experimental data for the rareearth elements were generally higher than the provisional values, often exceeding z-values of þ2. Determined values for Th and U in this reference material, for which certified values are available, were in excellent agreement.

American …, 2006

Sample introduction has been a problem for analytical chemists for decades. In 1984, Richard Brow... more Sample introduction has been a problem for analytical chemists for decades. In 1984, Richard Browner and Andrew Boorn went so far as to call sample introduction “The Achil-les' Heel of Atomic Spectroscopy.”1 Since that time, a multitude of varia-tions have been developed ...

Biochemical and Biophysical Research Communications, 2019

Lithium, a well-known inhibitor of glycogen synthase kinase-3b (GSK3b), can improve bone formatio... more Lithium, a well-known inhibitor of glycogen synthase kinase-3b (GSK3b), can improve bone formation by activating the Wnt/b-catenin signalling pathway. However, most studies have used higher doses of lithium, which potentially have adverse effects. Herein, we report that low dose lithium supplementation (10 mg/kg/d for 6 weeks) in mice results in a serum lithium concentration of 0.02 mM significantly inhibiting GSK3b while activating Wnt/b-catenin in bone. In turn, we observed a significant increase in the expression of osteoprotegerin (OPG), with unaltered expression of nuclear-factor kb ligand (RANKL), ultimately leading to a significant increase in the OPG/RANKL ratio. Altogether, our findings provide initial evidence that low dose lithium supplementation can promote the signalling pathways associated with bone formation.

Environmental Pollution, 2020

Passive samplers are useful tools for monitoring hydrophobic, persistent, and potentially bioaccu... more Passive samplers are useful tools for monitoring hydrophobic, persistent, and potentially bioaccumulative contaminants in the environment. In this study, low density polyethylene passive samplers were deployed in urban-influenced and background nearshore freshwaters of northwestern Lake Ontario and analyzed for a broad range of both legacy halogenated organic contaminants (HOCs) and halogenated flame retardants (HFRs). Non-targeted analysis was conducted for screening additional halogenated substances. For most compounds, concentrations were greatest in the industrialized Hamilton Harbour and more generally at sites that have stronger influences of wastewater effluent discharges and stormwater run-off through rivers and creeks. Polychlorinated biphenyls (PCBs) remain the dominant class of HOCs in water, with dissolved-phase concentrations ranging from 10 to 4100 pg/L (ΣPCBs), followed by polybrominated diphenylethers (ΣPBDEs; 14-960 pg/L) and the organochlorine pesticides (OCPs; 22-290 pg/L). Several non-PBDE brominated flame retardants (nBFRs) and chlorinated Dechlorane-related compounds were detected, with hexabromocyclododecanes (ΣHBCDD; sum of 3 diastereoisomers) the most abundant (1.0-21 pg/L). Non-targeted screening of samples by high resolution mass spectrometry using Kendrick mass defect plots for data analysis indicated that several other halogenated compounds were present in waters at relatively high abundances compared to the flame retardants, based on semi-quantitative estimates. These included methyl-triclosan, four halogenated anisoles (2,4,6-tribromoanisole, dimethyl-trichloroanisole, pentachloroanisole, and pentachlorothioanisole), and pentachloro-aniline. Dissolved-phase methyl-triclosan was estimated to contribute up to approximately 40% of the summed target HOC concentrations. Polyethylene passive samplers provided an excellent medium for both non-targeted screening of HOCs not currently included in monitoring programs and tracking brominated and chlorinated chemicals slated for reductions in uses and emissions through international (Stockholm Convention) and binational (Great Lakes) agreements.

Journal of the American Society for Mass Spectrometry, Nov 1, 1993

Spectrochimica Acta Part B: Atomic Spectroscopy, May 1, 1996

Analyst, 2005

Static headspace sampling technique coupled with gas chromatography and mass spectrometry was use... more Static headspace sampling technique coupled with gas chromatography and mass spectrometry was used to investigate the presence of volatile 2-alkyl-3-methoxypyrazines in three different species of ladybugs of the Coccinellidae family. The species investigated were Coccinella septempunctata, Harmonia axyridis and Hippodemia convergens. 2-isopropyl-3-methoxypyrazine (IPMP) was identified in all three species with detectable levels of 2-sec-butyl-3-methoxypyrazine (SBMP) and 3-isobutyl-2-methoxypyrazines (IBMP) in only Hippodemia convergens and Harmonia axyridis species. Relative amounts of 2-alkyl-3-methoxypyrazines based on body mass showed that Hippodemia convergens had the highest levels of all three methoxypyrazines and Coccinella septempunctata the least.

American Journal of Enology and Viticulture, 2004

Chemischer Informationsdienst, Apr 22, 1980

Investigations into the use of experimental membranes (Empore), containing iminodiacetate residue... more Investigations into the use of experimental membranes (Empore), containing iminodiacetate residues, as well as Millipore SEP PAK cartridges, containing either acid or basic alumina, have been carried out at the Ontario Ministry of Environmental and Energy laboratories in Rexdale, Ontario. In this paper, we report the results of our investigations by ICP mass spectrometry of recoveries of metal ions from drinking and surface waters.

Journal of the American Chemical Society, 2006

Talanta, Feb 1, 2016

Focused infrared radiation-based digestions, for the determination of gold and silver, can be ach... more Focused infrared radiation-based digestions, for the determination of gold and silver, can be achieved in a timeframe as short as 10-15min, making it an attractive candidate technology for the mining industry, where very large numbers of samples are analyzed on a daily basis. An investigation was carried out into gold and silver dissolution chemistry from geological samples using this novel digestion technique. This study investigated in-depth the issue of low recoveries of gold from aqua regia (AR) digestions, reported by a number of researchers. Conventional AR digestions consistently delivered gold recoveries in a range of 69-80% of the certified values for the four certified reference materials (CRM) employed (CCU-1d, SN26, OREAS 62c, and AMiS 0274), while silver recoveries were satisfactory. By gradually shifting the HCl:HNO3 ratio (v/v) from 3:1 to a reversed 1:3 ratio, recoveries of gold and silver exhibited inverse trends. At a HCl:HNO3 ratio of 1:3, complete recovery of gold was achieved with excellent reproducibility in all CRMs. Meanwhile, silver recoveries plunged significantly at this ratio in samples with higher silver concentrations. Silver values were recovered, however, when the silver was re-solubilized by adding a small volume of concentrated HCl to the cooled reverse aqua regia digests. Recoveries of base metals, such as Fe and Cu, were satisfactory throughout and were much less sensitive to changes in the digestion medium. Using four CRMs and five real-world gold/silver containing samples, the utility of the proposed reverse aqua regia was systematically studied. The uncomplicated nature of the digestion methods reported here, that are fast, effective and inexpensive, may be useful to analysts developing/optimizing their methods for the rapid determination of Au and Ag in a variety of mineral phases, particularly where rapid results are desirable, such as in prospecting and mine development.

Analytical and Bioanalytical Chemistry, Dec 2, 2009

Until recently, atmospheric pressure photoionization (APPI) has typically been used for the deter... more Until recently, atmospheric pressure photoionization (APPI) has typically been used for the determination of non-polar halogenated flame retardants (HFRs) by liquid chromatography (LC) tandem mass spectrometry. In this study, we demonstrated the feasibility of utilizing liquid chromatography atmospheric pressure chemical ionization (APCI) tandem mass spectrometry (LC-APCI-MS/MS) for analysis of 38 HFRs. This developed method offered three advantages: simplicity, rapidity, and high sensitivity. Compared with APPI, APCI does not require a UV lamp and a dopant reagent to assist atmospheric pressure ionization. All the isomers and the isobaric compounds were well resolved within 14-min LC separation time. Excellent instrument detection limits (6.1 pg on average with 2.0 μL injection) were observed. The APCI mechanism was also investigated. The method developed has been applied to the screening of wastewater samples for screening purpose, with concentrations determined by LC-APCI-MS/MS agreeing with data obtained via gas chromatography high resolution mass spectrometry. Keywords Atmospheric pressure chemical ionization (APCI). Liquid chromatography tandem mass spectrometry (LC-MS/MS). Halogenated flame retardants (HFRs). Wastewater

Rapid Communications in Mass Spectrometry, Jan 7, 2011

Although the two flame retardants 1,2‐dibromo‐4‐(1,2‐dibromoethyl)cyclohexane (TBECH) and 1,2,5,6... more Although the two flame retardants 1,2‐dibromo‐4‐(1,2‐dibromoethyl)cyclohexane (TBECH) and 1,2,5,6‐tetrabromocyclooctane (TBCO) have been widely used, a selective instrumental method of analysis for these compounds has not been developed to date. In this study, we demonstrate the feasibility to utilize liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the separation and analysis of α‐ and β‐TBCO and α‐, β‐, γ‐, and δ‐TBECH. Acetone was initially used in a tetrahedron solvent system for LC optimization. A simple isocratic elution allowed near‐baseline separation of these compounds. Different ionization approaches and mechanisms were investigated. The mass spectrometric transition of [M + O2]– => Br– (459.8 => 78.9) was a selective detection method for the target analytes. Good instrument detection limits (5 pg for γ‐/δ‐TBECH, 125 pg for α‐/β‐TBECH, and 30 pg for α‐/β‐TBCO with 2.0 µL injection) were obtained. Excellent linearity up to 50 ng/µL (R2 >0.999) was also achieved. This method has been applied to environmental samples (surface water) for screening purposes with recoveries ranging from 76–92% (CV%: 5–8%). This method shows significant improvement over previous methods. Copyright © 2011 John Wiley & Sons, Ltd.

Rapid Communications in Mass Spectrometry, Jan 7, 2011

In this work, we evaluate the performance of liquid chromatography-atmospheric pressure photoioni... more In this work, we evaluate the performance of liquid chromatography-atmospheric pressure photoionization-mass spectrometry (LC-APPI-MS) for non-aqueous reversed phase analysis of six triacylglycerol model compounds using six binary mobile phases including MeOH/iPrOH, MeOH/CHCl 3 , MeOH/CH 2 Cl 2 , CH 3 CN/iPrOH, CH 3 CN/CHCl 3 , and CH 3 CN/CH 2 Cl 2. All mobile phases give comparably good separation performance on a Gemini C 18 column with carefully adjusted gradient elution programs. APPI sensitivity varies from one mobile phase to the other without dopants; however use of dopants brings sensitivity to comparable levels for all mobile phases. MeOH/iPrOH offers high sensitivity without dopants due to self-doping effect and dopants are not necessary for this mobile phase. Dopants enhance analyte sensitivity to a varying degree for each of the mobile phases tested. Photo-induced chemical ionization (PCI) of solvent may play a significant role in achieving high sensitivity. Two critical parameters affecting sensitivity are photoabsorption cross-sections and ionization potentials of mobile phase solvents. How these mobile phase solvents affect APPI sensitivity and their dependency on dopant use are discussed. All six mobile phases offer comparable overall limits of detection for the analytes tested. These results indicate that LC-APPI-MS is a successful tool for neutral lipid analysis, giving high sensitivity with a variety of non-aqueous mobile phases.

Environmental Pollution, Nov 1, 2008

This study determines spatial trends and congener patterns of 2378-substituted polychlorinated di... more This study determines spatial trends and congener patterns of 2378-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in surficial sediments of Lakes Erie and Ontario. Sediments are enriched in 2378-PCDFs in Lake Ontario, and the PCDD/F concentrations increased from shallow near-shore sediments towards deep-water depositional zone sediments. In Lake Erie, sediments were dominated by octachlorodibenzo-p-dioxin, and the highest PCDD/F concentrations were observed in the western basin and the southern shoreline of the central basin with a decrease towards the eastern basin and the northern shoreline of the central basin. Principal components analysis revealed that chemical manufacture and disposal of chemical waste along the Niagara River has been a major PCDD/F source to Lake Ontario; while PCDD/Fs in Lake Erie are from multiple sources including industrial sources along the Detroit River, major tributaries along the southern shoreline of the lake, and atmospherically-derived material from the upper lakes and connecting channels.

HAL (Le Centre pour la Communication Scientifique Directe), Jun 8, 2007

Talanta, 2016

Short-wavelength infrared radiation has been successfully applied to accelerate the acid digestio... more Short-wavelength infrared radiation has been successfully applied to accelerate the acid digestion of refractory rare-earth ore samples. Determinations were achieved with microwave plasma-atomic emission spectrometry (MP-AES) and dynamic reaction cellinductively coupled plasma-mass spectrometry (DRC-ICP-MS). The digestion method developed was able to tackle high iron-oxide and silicate matrices using only phosphoric acid in a time frame of only 8 min, and did not require perchloric or hydrofluoric acid. Additionally, excellent recoveries and reproducibilities of the rare earth elements, as well as uranium and thorium, were achieved. Digestions of the certified reference materials OREAS-465 and REE-1, with radically different mineralogies, delivered results that mirror those obtained by fusion processes. For the rare-earth CRM OKA-2, whose REE data are provisional, experimental data for the rareearth elements were generally higher than the provisional values, often exceeding z-values of þ2. Determined values for Th and U in this reference material, for which certified values are available, were in excellent agreement.

American …, 2006

Sample introduction has been a problem for analytical chemists for decades. In 1984, Richard Brow... more Sample introduction has been a problem for analytical chemists for decades. In 1984, Richard Browner and Andrew Boorn went so far as to call sample introduction “The Achil-les' Heel of Atomic Spectroscopy.”1 Since that time, a multitude of varia-tions have been developed ...

Biochemical and Biophysical Research Communications, 2019

Lithium, a well-known inhibitor of glycogen synthase kinase-3b (GSK3b), can improve bone formatio... more Lithium, a well-known inhibitor of glycogen synthase kinase-3b (GSK3b), can improve bone formation by activating the Wnt/b-catenin signalling pathway. However, most studies have used higher doses of lithium, which potentially have adverse effects. Herein, we report that low dose lithium supplementation (10 mg/kg/d for 6 weeks) in mice results in a serum lithium concentration of 0.02 mM significantly inhibiting GSK3b while activating Wnt/b-catenin in bone. In turn, we observed a significant increase in the expression of osteoprotegerin (OPG), with unaltered expression of nuclear-factor kb ligand (RANKL), ultimately leading to a significant increase in the OPG/RANKL ratio. Altogether, our findings provide initial evidence that low dose lithium supplementation can promote the signalling pathways associated with bone formation.

Environmental Pollution, 2020

Passive samplers are useful tools for monitoring hydrophobic, persistent, and potentially bioaccu... more Passive samplers are useful tools for monitoring hydrophobic, persistent, and potentially bioaccumulative contaminants in the environment. In this study, low density polyethylene passive samplers were deployed in urban-influenced and background nearshore freshwaters of northwestern Lake Ontario and analyzed for a broad range of both legacy halogenated organic contaminants (HOCs) and halogenated flame retardants (HFRs). Non-targeted analysis was conducted for screening additional halogenated substances. For most compounds, concentrations were greatest in the industrialized Hamilton Harbour and more generally at sites that have stronger influences of wastewater effluent discharges and stormwater run-off through rivers and creeks. Polychlorinated biphenyls (PCBs) remain the dominant class of HOCs in water, with dissolved-phase concentrations ranging from 10 to 4100 pg/L (ΣPCBs), followed by polybrominated diphenylethers (ΣPBDEs; 14-960 pg/L) and the organochlorine pesticides (OCPs; 22-290 pg/L). Several non-PBDE brominated flame retardants (nBFRs) and chlorinated Dechlorane-related compounds were detected, with hexabromocyclododecanes (ΣHBCDD; sum of 3 diastereoisomers) the most abundant (1.0-21 pg/L). Non-targeted screening of samples by high resolution mass spectrometry using Kendrick mass defect plots for data analysis indicated that several other halogenated compounds were present in waters at relatively high abundances compared to the flame retardants, based on semi-quantitative estimates. These included methyl-triclosan, four halogenated anisoles (2,4,6-tribromoanisole, dimethyl-trichloroanisole, pentachloroanisole, and pentachlorothioanisole), and pentachloro-aniline. Dissolved-phase methyl-triclosan was estimated to contribute up to approximately 40% of the summed target HOC concentrations. Polyethylene passive samplers provided an excellent medium for both non-targeted screening of HOCs not currently included in monitoring programs and tracking brominated and chlorinated chemicals slated for reductions in uses and emissions through international (Stockholm Convention) and binational (Great Lakes) agreements.