Takeo Sakuma | York University (original) (raw)

Papers by Takeo Sakuma

Journal of Chromatography A, Apr 1, 2001

We report on the transformation of tamoxifen at 378C in synthetic gastric fluid as studied by hig... more We report on the transformation of tamoxifen at 378C in synthetic gastric fluid as studied by high-performance liquid chromatography with triple quadrupole mass spectrometry. The major transformation products detected were (E)-isomer of tamoxifen, metabolite D, and several unidentified components having m /z 404. Addition of pepsin to the gastric fluid inhibited formation of all of these products. We analyzed several urine samples from breast cancer patients undergoing tamoxifen treatment. Metabolite D was identified in the urine samples and in the gastric fluid digest at a retention time of 22.0 min eluting from a reversed-phase HPLC column. Although several metabolites were found in all the urine samples of patients, some metabolites were detected in one sample but not others, suggesting tamoxifen metabolism varies in patients.

Environmental Science & Technology, Aug 12, 2014

To analyze the naphthenic acid content of environmental waters quickly and efficiently, we have d... more To analyze the naphthenic acid content of environmental waters quickly and efficiently, we have developed a method that employs differential mobility spectrometry (DMS) coupled to mass spectrometry (MS). This technique combines the benefits of infusion-based MS experiments (parallel, on-demand access to individual components) with DMS's ability to provide liquid chromatography-like separations of isobaric and isomeric compounds in a fraction of the time. In this study, we have applied a DMS-MS workflow to the rapid gas-phase separation of naphthenic acids (NAs) within a technical standard and a real-world oil sands process-affected water (OSPW) extract. Among the findings provided by this workflow are the rapid characterization of isomeric NAs (i.e., same molecular formulas) in a complex OSPW sample, the ability to use DMS to isolate individual NA components (including isomeric NAs) for in-depth structural analyses, and a method by which NA analytes, background ions, and dimer species can be characterized by their distinct behaviors in DMS. Overall, the profiles of the NA content of the technical and OSPW samples were consistent with published values for similar samples, such that the benefits of DMS technology do not detract from the workflow's accuracy or quality.

Planta Medica, Mar 7, 2012

Springer eBooks, 1980

Polynuclear aromatic hydrocarbons (PAH) are widely distributed in the atmospheric and water envir... more Polynuclear aromatic hydrocarbons (PAH) are widely distributed in the atmospheric and water environments. These compounds occur in diverse sources such as combustion products of fossil fuels, motor vehicle exhaust, fumes from coke ovens, incineration of refuse, liquid effluents from petroleum, petrochemical and many other industrial operations. Airborne particlate matter, which contains PAH, contributes to the pollution of water supplies by sedimentation, impaction and precipitation on land and water surfaces. The sources, reactivity, metabolism and carcinogenic properties of PAH have been reviewed in a monograph by the U.S. National Academy of Sciences (1972). Some PAH compounds have been shown to be potent carcinogens in biological assays but isomers of a specific group may differ greatly in potency. Thus, benzo(a)pyrene is a strong carcinogen, whereas the isomeric benzo(e)pyrene is non-carcinogenic; benzo(b)fluoranthene is carcinogenic but benzo(k) fluoranthene is negative. Similarly, benz(a)anthracene is positively carcinogenic, whereas the isomeric chrysene has been reported as negative or only weakly carcinogenic.

ABSTRACT A sensitive, selective and fast method was developed for the analysis of Testosterone an... more ABSTRACT A sensitive, selective and fast method was developed for the analysis of Testosterone and Warfarin in rat plasma from in vivo pharmacokinetic experiments. The instrumentation consisted of TurboFlow® Chromatography (TFC) coupled with an API ...

Journal of Food and Drug Analysis, Jul 14, 2020

Planta Medica, Mar 7, 2012

Lc Gc North America, 2005

erchlorate has received widespread attention as an environmental pollutant over the past several ... more erchlorate has received widespread attention as an environmental pollutant over the past several years. Perchlorate was most recently monitored for occurrence in drinking waters under U.S. EPA’s first Unregulated Contaminated Monitoring Rule (UCMR) using an ion chromatography (IC) suppressed conductivity detection technique according to the procedural requirements of EPA Method 314.0. Based on the monitoring data collected during UCMR, the U.S. EPA proposed a regulatory limit for perchlorate in drinking water of 1 mg/L. In addition, new methods capable of reliable determination of perchlorate safely below this limit have been developed by U.S. EPA, including Methods 314.1, 331.0, and 332.0. Method 332.0 relies on an IC separation with either mass spectrometry (MS) or tandem mass spectrometry (MS-MS) for detection and quantitation. This application note demonstrates the use and advantages of IC–MS-MS per Method 332.0 (1).

Hydrocarbons and Halogenated Hydrocarbons in the Aquatic Environment, 1980

Polynuclear aromatic hydrocarbons (PAH) are widely distributed in the atmospheric and water envir... more Polynuclear aromatic hydrocarbons (PAH) are widely distributed in the atmospheric and water environments. These compounds occur in diverse sources such as combustion products of fossil fuels, motor vehicle exhaust, fumes from coke ovens, incineration of refuse, liquid effluents from petroleum, petrochemical and many other industrial operations. Airborne particlate matter, which contains PAH, contributes to the pollution of water supplies by sedimentation, impaction and precipitation on land and water surfaces. The sources, reactivity, metabolism and carcinogenic properties of PAH have been reviewed in a monograph by the U.S. National Academy of Sciences (1972). Some PAH compounds have been shown to be potent carcinogens in biological assays but isomers of a specific group may differ greatly in potency. Thus, benzo(a)pyrene is a strong carcinogen, whereas the isomeric benzo(e)pyrene is non-carcinogenic; benzo(b)fluoranthene is carcinogenic but benzo(k) fluoranthene is negative. Similarly, benz(a)anthracene is positively carcinogenic, whereas the isomeric chrysene has been reported as negative or only weakly carcinogenic.

Environmental science & technology, Jan 2, 2014

To analyze the naphthenic acid content of environmental waters quickly and efficiently, we have d... more To analyze the naphthenic acid content of environmental waters quickly and efficiently, we have developed a method that employs differential mobility spectrometry (DMS) coupled to mass spectrometry (MS). This technique combines the benefits of infusion-based MS experiments (parallel, on-demand access to individual components) with DMS's ability to provide liquid chromatography-like separations of isobaric and isomeric compounds in a fraction of the time. In this study, we have applied a DMS-MS workflow to the rapid gas-phase separation of naphthenic acids (NAs) within a technical standard and a real-world oil sands process-affected water (OSPW) extract. Among the findings provided by this workflow are the rapid characterization of isomeric NAs (i.e., same molecular formulas) in a complex OSPW sample, the ability to use DMS to isolate individual NA components (including isomeric NAs) for in-depth structural analyses, and a method by which NA analytes, background ions, and dimer s...

Journal of Chromatography A, 2001

We report on the transformation of tamoxifen at 378C in synthetic gastric fluid as studied by hig... more We report on the transformation of tamoxifen at 378C in synthetic gastric fluid as studied by high-performance liquid chromatography with triple quadrupole mass spectrometry. The major transformation products detected were (E)-isomer of tamoxifen, metabolite D, and several unidentified components having m /z 404. Addition of pepsin to the gastric fluid inhibited formation of all of these products. We analyzed several urine samples from breast cancer patients undergoing tamoxifen treatment. Metabolite D was identified in the urine samples and in the gastric fluid digest at a retention time of 22.0 min eluting from a reversed-phase HPLC column. Although several metabolites were found in all the urine samples of patients, some metabolites were detected in one sample but not others, suggesting tamoxifen metabolism varies in patients.

appliedbiosystems.com

A sensitive, selective and fast method was developed for the analysis of Testosterone and Warfari... more A sensitive, selective and fast method was developed for the analysis of Testosterone and Warfarin in rat plasma from in vivo pharmacokinetic experiments. The instrumentation consisted of TurboFlow® Chromatography (TFC) coupled with an API ...

Analytical Chemistry, 1999

An HPLC/MS/MS method has been developed for the characterization and quantification of ginsenosid... more An HPLC/MS/MS method has been developed for the characterization and quantification of ginsenosides contained in extracts of the root of Panax ginseng (Korean ginsengs) and Panax quinquefolius L. (American ginsengs). The [M + H]+ and [M + Na]+ ions were observed for ginsenoside standards (Rb1, Rb2, Rc, Rd, Re, Rf, Rg1) and four different ginseng extracts. The glycosidic linkages, the core, and the attached sugar(s) of the ginsenosides can be determined from the collision-induced dissociation spectra from the protonated molecules. The relative distribution of these ginsenosides in each extract of American or Korean ginseng was established.

Analytica Chimica Acta, 2003

A procedure to extract polycyclic aromatic hydrocarbons (PAHs) from airborne particles using open... more A procedure to extract polycyclic aromatic hydrocarbons (PAHs) from airborne particles using open-vessel focused microwave-assisted extraction (FMAE) is proposed. Parameters which might affect extraction efficiency such as solvent composition, extraction time, microwave power, and sample water addition were investigated. Recoveries for PAHs from urban dust standard reference material (SRM) 1649a were between 77 and 116% with relative standard deviations between 2 and 18% on the basis of certified values by using an optimized condition: in a 20 ml 5% acetone in toluene at 150 W of microwave power for 20 min extraction. The optimized FMAE condition was compared to Soxhlet method on the extraction of standard reference material and real particulate air samples collected from urban area.

Clinical Biochemistry, 2008

The ARCHITECT functional sensitivity (20% CV, 95% CI) ranged from 16.0 to 21.8 ng/mL. The total %... more The ARCHITECT functional sensitivity (20% CV, 95% CI) ranged from 16.0 to 21.8 ng/mL. The total %CVs were 7.5-11.1% at 87.5 ng/ mL, 6.6-14.3% at 411 ng/mL, and 5.2-10.7% at 916 ng/mL. The following results were obtained in patient correlation studies: ARCHITECT CsA vs. LC/MS/MS yielded a Spearman r value of 0.99, a regression equation of y = 1.10x − 7.1, and an average bias of 30.7 ng/mL; ARCHITECT CsA vs. Dimension Xpand yielded a range of Spearman r values of 0.93 to 0.98, slopes of 0.69 to 1.08, y-intercepts of − 20.1 to 26.1 ng/mL, and an average bias range of − 76.2 to − 6.7 ng/mL (4 sites). Conclusion: The ARCHITECT CsA assay has reduced CsA metabolite interference relative to Dade Dimension.

Pharmaceutical Research, 2008

To evaluate the sensitivity requirement for LC-MS/MS as an analytical tool to support human micro... more To evaluate the sensitivity requirement for LC-MS/MS as an analytical tool to support human microdosing study with sub-pharmacological dose, investigate proportionality of pharmacokinetics from the microdose to therapeutic human equivalent doses in rats and characterize circulating metabolites in rats administered with the microdose. Five drugs of antipyrine, metoprolol, carbamazepine, digoxin and atenolol were administered orally to male Sprague-Dawley rats at 0.167, 1.67, 16.7, 167 and 1,670 microg/kg doses. Plasma samples were extracted using either solid phase extraction or liquid-liquid extraction, and analyzed using LC-MS/MS. Using 100 microl of plasma sample, the lower limit of quantitation for antipyrine (10 pg/ml), carbamazepine (1 pg/ml), metoprolol (5 pg/ml), atenolol (20 pg/ml), and digoxin (5 pg/ml) were achieved using an API 5000. Proportional pharmacokinetics were observed from 0.167 microg/kg to 1,670 microg/kg for antipyrine and carbamazepine and from 1.67 to 1,670 microg/kg for atenolol and digoxin, while metoprolol exhibited a non-proportional pharmacokinetics relationship. Several metabolites of carbamazepine were characterized in plasma from rats dosed at 1.67 mug/kg using LC-MS/MS. This study has shown the promise of sensitive LC-MS/MS method to support microdose pharmacokinetics and drug metabolism studies in human.

Journal of Chromatography A, Apr 1, 2001

We report on the transformation of tamoxifen at 378C in synthetic gastric fluid as studied by hig... more We report on the transformation of tamoxifen at 378C in synthetic gastric fluid as studied by high-performance liquid chromatography with triple quadrupole mass spectrometry. The major transformation products detected were (E)-isomer of tamoxifen, metabolite D, and several unidentified components having m /z 404. Addition of pepsin to the gastric fluid inhibited formation of all of these products. We analyzed several urine samples from breast cancer patients undergoing tamoxifen treatment. Metabolite D was identified in the urine samples and in the gastric fluid digest at a retention time of 22.0 min eluting from a reversed-phase HPLC column. Although several metabolites were found in all the urine samples of patients, some metabolites were detected in one sample but not others, suggesting tamoxifen metabolism varies in patients.

Environmental Science & Technology, Aug 12, 2014

To analyze the naphthenic acid content of environmental waters quickly and efficiently, we have d... more To analyze the naphthenic acid content of environmental waters quickly and efficiently, we have developed a method that employs differential mobility spectrometry (DMS) coupled to mass spectrometry (MS). This technique combines the benefits of infusion-based MS experiments (parallel, on-demand access to individual components) with DMS's ability to provide liquid chromatography-like separations of isobaric and isomeric compounds in a fraction of the time. In this study, we have applied a DMS-MS workflow to the rapid gas-phase separation of naphthenic acids (NAs) within a technical standard and a real-world oil sands process-affected water (OSPW) extract. Among the findings provided by this workflow are the rapid characterization of isomeric NAs (i.e., same molecular formulas) in a complex OSPW sample, the ability to use DMS to isolate individual NA components (including isomeric NAs) for in-depth structural analyses, and a method by which NA analytes, background ions, and dimer species can be characterized by their distinct behaviors in DMS. Overall, the profiles of the NA content of the technical and OSPW samples were consistent with published values for similar samples, such that the benefits of DMS technology do not detract from the workflow's accuracy or quality.

Planta Medica, Mar 7, 2012

Springer eBooks, 1980

Polynuclear aromatic hydrocarbons (PAH) are widely distributed in the atmospheric and water envir... more Polynuclear aromatic hydrocarbons (PAH) are widely distributed in the atmospheric and water environments. These compounds occur in diverse sources such as combustion products of fossil fuels, motor vehicle exhaust, fumes from coke ovens, incineration of refuse, liquid effluents from petroleum, petrochemical and many other industrial operations. Airborne particlate matter, which contains PAH, contributes to the pollution of water supplies by sedimentation, impaction and precipitation on land and water surfaces. The sources, reactivity, metabolism and carcinogenic properties of PAH have been reviewed in a monograph by the U.S. National Academy of Sciences (1972). Some PAH compounds have been shown to be potent carcinogens in biological assays but isomers of a specific group may differ greatly in potency. Thus, benzo(a)pyrene is a strong carcinogen, whereas the isomeric benzo(e)pyrene is non-carcinogenic; benzo(b)fluoranthene is carcinogenic but benzo(k) fluoranthene is negative. Similarly, benz(a)anthracene is positively carcinogenic, whereas the isomeric chrysene has been reported as negative or only weakly carcinogenic.

ABSTRACT A sensitive, selective and fast method was developed for the analysis of Testosterone an... more ABSTRACT A sensitive, selective and fast method was developed for the analysis of Testosterone and Warfarin in rat plasma from in vivo pharmacokinetic experiments. The instrumentation consisted of TurboFlow® Chromatography (TFC) coupled with an API ...

Journal of Food and Drug Analysis, Jul 14, 2020

Planta Medica, Mar 7, 2012

Lc Gc North America, 2005

erchlorate has received widespread attention as an environmental pollutant over the past several ... more erchlorate has received widespread attention as an environmental pollutant over the past several years. Perchlorate was most recently monitored for occurrence in drinking waters under U.S. EPA’s first Unregulated Contaminated Monitoring Rule (UCMR) using an ion chromatography (IC) suppressed conductivity detection technique according to the procedural requirements of EPA Method 314.0. Based on the monitoring data collected during UCMR, the U.S. EPA proposed a regulatory limit for perchlorate in drinking water of 1 mg/L. In addition, new methods capable of reliable determination of perchlorate safely below this limit have been developed by U.S. EPA, including Methods 314.1, 331.0, and 332.0. Method 332.0 relies on an IC separation with either mass spectrometry (MS) or tandem mass spectrometry (MS-MS) for detection and quantitation. This application note demonstrates the use and advantages of IC–MS-MS per Method 332.0 (1).

Hydrocarbons and Halogenated Hydrocarbons in the Aquatic Environment, 1980

Polynuclear aromatic hydrocarbons (PAH) are widely distributed in the atmospheric and water envir... more Polynuclear aromatic hydrocarbons (PAH) are widely distributed in the atmospheric and water environments. These compounds occur in diverse sources such as combustion products of fossil fuels, motor vehicle exhaust, fumes from coke ovens, incineration of refuse, liquid effluents from petroleum, petrochemical and many other industrial operations. Airborne particlate matter, which contains PAH, contributes to the pollution of water supplies by sedimentation, impaction and precipitation on land and water surfaces. The sources, reactivity, metabolism and carcinogenic properties of PAH have been reviewed in a monograph by the U.S. National Academy of Sciences (1972). Some PAH compounds have been shown to be potent carcinogens in biological assays but isomers of a specific group may differ greatly in potency. Thus, benzo(a)pyrene is a strong carcinogen, whereas the isomeric benzo(e)pyrene is non-carcinogenic; benzo(b)fluoranthene is carcinogenic but benzo(k) fluoranthene is negative. Similarly, benz(a)anthracene is positively carcinogenic, whereas the isomeric chrysene has been reported as negative or only weakly carcinogenic.

Environmental science & technology, Jan 2, 2014

To analyze the naphthenic acid content of environmental waters quickly and efficiently, we have d... more To analyze the naphthenic acid content of environmental waters quickly and efficiently, we have developed a method that employs differential mobility spectrometry (DMS) coupled to mass spectrometry (MS). This technique combines the benefits of infusion-based MS experiments (parallel, on-demand access to individual components) with DMS's ability to provide liquid chromatography-like separations of isobaric and isomeric compounds in a fraction of the time. In this study, we have applied a DMS-MS workflow to the rapid gas-phase separation of naphthenic acids (NAs) within a technical standard and a real-world oil sands process-affected water (OSPW) extract. Among the findings provided by this workflow are the rapid characterization of isomeric NAs (i.e., same molecular formulas) in a complex OSPW sample, the ability to use DMS to isolate individual NA components (including isomeric NAs) for in-depth structural analyses, and a method by which NA analytes, background ions, and dimer s...

Journal of Chromatography A, 2001

We report on the transformation of tamoxifen at 378C in synthetic gastric fluid as studied by hig... more We report on the transformation of tamoxifen at 378C in synthetic gastric fluid as studied by high-performance liquid chromatography with triple quadrupole mass spectrometry. The major transformation products detected were (E)-isomer of tamoxifen, metabolite D, and several unidentified components having m /z 404. Addition of pepsin to the gastric fluid inhibited formation of all of these products. We analyzed several urine samples from breast cancer patients undergoing tamoxifen treatment. Metabolite D was identified in the urine samples and in the gastric fluid digest at a retention time of 22.0 min eluting from a reversed-phase HPLC column. Although several metabolites were found in all the urine samples of patients, some metabolites were detected in one sample but not others, suggesting tamoxifen metabolism varies in patients.

appliedbiosystems.com

A sensitive, selective and fast method was developed for the analysis of Testosterone and Warfari... more A sensitive, selective and fast method was developed for the analysis of Testosterone and Warfarin in rat plasma from in vivo pharmacokinetic experiments. The instrumentation consisted of TurboFlow® Chromatography (TFC) coupled with an API ...

Analytical Chemistry, 1999

An HPLC/MS/MS method has been developed for the characterization and quantification of ginsenosid... more An HPLC/MS/MS method has been developed for the characterization and quantification of ginsenosides contained in extracts of the root of Panax ginseng (Korean ginsengs) and Panax quinquefolius L. (American ginsengs). The [M + H]+ and [M + Na]+ ions were observed for ginsenoside standards (Rb1, Rb2, Rc, Rd, Re, Rf, Rg1) and four different ginseng extracts. The glycosidic linkages, the core, and the attached sugar(s) of the ginsenosides can be determined from the collision-induced dissociation spectra from the protonated molecules. The relative distribution of these ginsenosides in each extract of American or Korean ginseng was established.

Analytica Chimica Acta, 2003

A procedure to extract polycyclic aromatic hydrocarbons (PAHs) from airborne particles using open... more A procedure to extract polycyclic aromatic hydrocarbons (PAHs) from airborne particles using open-vessel focused microwave-assisted extraction (FMAE) is proposed. Parameters which might affect extraction efficiency such as solvent composition, extraction time, microwave power, and sample water addition were investigated. Recoveries for PAHs from urban dust standard reference material (SRM) 1649a were between 77 and 116% with relative standard deviations between 2 and 18% on the basis of certified values by using an optimized condition: in a 20 ml 5% acetone in toluene at 150 W of microwave power for 20 min extraction. The optimized FMAE condition was compared to Soxhlet method on the extraction of standard reference material and real particulate air samples collected from urban area.

Clinical Biochemistry, 2008

The ARCHITECT functional sensitivity (20% CV, 95% CI) ranged from 16.0 to 21.8 ng/mL. The total %... more The ARCHITECT functional sensitivity (20% CV, 95% CI) ranged from 16.0 to 21.8 ng/mL. The total %CVs were 7.5-11.1% at 87.5 ng/ mL, 6.6-14.3% at 411 ng/mL, and 5.2-10.7% at 916 ng/mL. The following results were obtained in patient correlation studies: ARCHITECT CsA vs. LC/MS/MS yielded a Spearman r value of 0.99, a regression equation of y = 1.10x − 7.1, and an average bias of 30.7 ng/mL; ARCHITECT CsA vs. Dimension Xpand yielded a range of Spearman r values of 0.93 to 0.98, slopes of 0.69 to 1.08, y-intercepts of − 20.1 to 26.1 ng/mL, and an average bias range of − 76.2 to − 6.7 ng/mL (4 sites). Conclusion: The ARCHITECT CsA assay has reduced CsA metabolite interference relative to Dade Dimension.

Pharmaceutical Research, 2008

To evaluate the sensitivity requirement for LC-MS/MS as an analytical tool to support human micro... more To evaluate the sensitivity requirement for LC-MS/MS as an analytical tool to support human microdosing study with sub-pharmacological dose, investigate proportionality of pharmacokinetics from the microdose to therapeutic human equivalent doses in rats and characterize circulating metabolites in rats administered with the microdose. Five drugs of antipyrine, metoprolol, carbamazepine, digoxin and atenolol were administered orally to male Sprague-Dawley rats at 0.167, 1.67, 16.7, 167 and 1,670 microg/kg doses. Plasma samples were extracted using either solid phase extraction or liquid-liquid extraction, and analyzed using LC-MS/MS. Using 100 microl of plasma sample, the lower limit of quantitation for antipyrine (10 pg/ml), carbamazepine (1 pg/ml), metoprolol (5 pg/ml), atenolol (20 pg/ml), and digoxin (5 pg/ml) were achieved using an API 5000. Proportional pharmacokinetics were observed from 0.167 microg/kg to 1,670 microg/kg for antipyrine and carbamazepine and from 1.67 to 1,670 microg/kg for atenolol and digoxin, while metoprolol exhibited a non-proportional pharmacokinetics relationship. Several metabolites of carbamazepine were characterized in plasma from rats dosed at 1.67 mug/kg using LC-MS/MS. This study has shown the promise of sensitive LC-MS/MS method to support microdose pharmacokinetics and drug metabolism studies in human.