Evidence and quantitation of aromatic organosulfates in ambient aerosols in Lahore, Pakistan

Abstract. Organosulfates are important components of atmospheric organic aerosols, yet their structures, abundances, sources and formation processes are not adequately understood. This study presents the identification and quantitation of benzyl sulfate in atmospheric aerosols, which is the first confirmed atmospheric organosulfate with aromatic carbon backbone. Benzyl sulfate was identified and quantified in fine particulate matter (PM2.5) collected in Lahore, Pakistan, during 2007–2008. An authentic standard of benzyl sulfate was synthesized, standardized, and identified in atmospheric aerosols with quadrupole time-of-flight (Q-ToF) mass spectrometry (MS). Benzyl sulfate was quantified in aerosol samples using ultra performance liquid chromatography (UPLC) coupled to negative electrospray ionization triple quadrupole (TQ) MS. The highest benzyl sulfate concentrations were recorded in November and January 2007 (0.50 ± 0.11 ng m−3) whereas the lowest concentration was observed in July (0.05 ± 0.02 ng m−3). To evaluate matrix effects, benzyl sulfate concentrations were determined using external calibration and the method of standard addition; comparable concentrations were detected by the two methods, which ruled out significant matrix effects in benzyl sulfate quantitation. Three additional organosulfates with m/z 187, 201 and 215 were qualitatively identified as aromatic organosulfates with additional methyl substituents by high-resolution mass measurements and tandem MS. The observed aromatic organosulfates form a homologous series analogous to toluene, xylene, and trimethylbenzene, which are abundant anthropogenic volatile organic compounds (VOC), suggesting that aromatic organosulfates may be formed by secondary reactions. However, stronger statistical correlations of benzyl sulfate with combustion tracers (EC and levoglucosan) than with secondary tracers (SO42− and α-pinene-derived nitrooxy organosulfates) suggest that aromatic organosulfates may be emitted from the combustion sources or their subsequent atmospheric processing. Further studies are needed to elucidate the sources and formation pathways of aromatic organosulfates in the atmosphere.

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Evidence and quantitation of aromatic organosulfates in ambient aerosols in Lahore, Pakistan

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-32795-2012 ◽

2012 ◽

Vol 12 (12) ◽

pp. 32795-32823 ◽

Cited By ~ 1

Author(s):

S. Kundu ◽

T. A. Quraishi ◽

G. Yu ◽

C. Suarez ◽

F. N. Keutsch ◽

...

Keyword(s):

Atmospheric Aerosols ◽

Matrix Effects ◽

Fine Particulate Matter ◽

Standard Addition ◽

Ultra Performance Liquid Chromatography ◽

Mass Measurements ◽

Ambient Aerosols ◽

Volatile Organic ◽

Secondary Reactions ◽

Negative Electrospray Ionization

Abstract. Organosulfates are important components of atmospheric organic aerosols, yet their structures, abundances, sources and formation processes are not adequately understood. This study presents the identification and quantitation of benzyl sulfate in atmospheric aerosols, which is the first reported atmospheric organosulfate with aromatic carbon backbone. Benzyl sulfate was identified and quantified in fine particulate matter (PM2.5) collected in Lahore, Pakistan during 2007–2008. An authentic standard of benzyl sulfate was synthesized, standardized, and identified in atmospheric aerosols using ultra-performance liquid chromatography (UPLC) coupled with quadrupole time-of-flight (Q-ToF) mass spectrometry (MS). Benzyl sulfate was quantified in aerosol samples using UPLC coupled to negative electrospray ionization triple quadrupole (TQ) MS. The highest benzyl sulfate concentrations were recorded in November and January 2007 (0.50 ± 0.11 ng m−3) whereas the lowest concentration was observed in July (0.05 ± 0.02 ng m−3). To evaluate matrix effects, benzyl sulfate concentrations were determined using external calibration and the method of standard addition; comparable concentrations were detected by the two methods, which ruled out significant matrix effects in benzyl sulfate quantitation. Three additional organosulfates with m/z 187, 201 and 215 were qualitatively identified as aromatic organosulfates with additional methyl substituents by high-resolution mass measurements and tandem MS. The observed aromatic organosulfates form a homologous series analogous to toluene, xylene, and trimethylbenzene, which are abundant anthropogenic volatile organic compounds (VOC), suggesting that aromatic organosulfates may be formed by secondary reactions. Further studies are needed to elucidate the sources and formation pathways of aromatic organosulfates in the atmosphere.

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Simultaneous quantification method for 5-FU, uracil, and tegafur using UPLC-MS/MS and clinical application in monitoring UFT/LV combination therapy after hepatectomy

Scientific Reports ◽

10.1038/s41598-021-82908-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ken Shiraiwa ◽

Yosuke Suzuki ◽

Hiroki Uchida ◽

Yukio Iwashita ◽

Ryota Tanaka ◽

...

Keyword(s):

Adverse Effects ◽

Combination Therapy ◽

Human Plasma ◽

Matrix Effects ◽

Ultra Performance Liquid Chromatography ◽

Therapeutic Drug ◽

Simultaneous Quantification ◽

Ionization Mode ◽

Time Courses ◽

Negative Electrospray Ionization

AbstractCombination therapy of tegafur/uracil (UFT) and leucovorin (LV) is widely used to treat colorectal cancers. Although this therapy has a significant therapeutic effect, severe adverse effects occur frequently. Therapeutic drug monitoring (TDM) may help to prevent adverse effects. A useful assay that can quantitate plasma levels of 5-FU, uracil, and tegafur simultaneously for TDM has been desired, but such a method is not currently available. In this study, we aimed to develop a sensitive method for simultaneous quantification of 5-FU, uracil, and tegafur in human plasma using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). After preparing plasma samples by protein precipitation and liquid extraction, 5-FU, uracil, and tegafur were analyzed by UPLC-MS/MS in negative electrospray ionization mode. Validation was performed according to US Food and Drugs Administration guidance. The calibration curves were linear over concentration ranges of 2–500 ng/mL for 5-FU, 20–5000 ng/mL for uracil, and 200–50,000 ng/mL for tegafur. The corresponding average recovery rates were 79.9, 80.9, and 87.8%. The method provides accuracy within 11.6% and precision below 13.3% for all three analytes. Matrix effects of 5-FU, uracil, and tegafur were higher than 43.5, 84.9, and 100.2%, respectively. This assay was successfully applied to assess the time courses of plasma 5-FU, uracil, and tegafur concentrations in two patients with colorectal liver metastasis who received UFT/LV therapy after hepatectomy. In conclusion, we succeeded to develop a sensitive and robust UPLC-MS/MS method for simultaneous quantification of 5-FU, uracil, and tegafur in human plasma. This method is potentially useful for TDM in patients receiving UFT/LV combination therapy.

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Development, characterization and first deployment of an improved online reactive oxygen species analyzer

10.5194/amt-2017-161 ◽

2017 ◽

Cited By ~ 2

Author(s):

Jun Zhou ◽

Emily A. Bruns ◽

Peter Zotter ◽

Giulia Stefenelli ◽

André S. H. Prévôt ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Detection Limit ◽

Atmospheric Aerosols ◽

Matrix Effects ◽

Reactive Oxygen ◽

Oxygen Species ◽

Wood Combustion ◽

Ambient Aerosols ◽

Storage Duration ◽

High Concentrations

Abstract. Inhalation of atmospheric particles is linked to human diseases. Reactive oxygen species (ROS) present in these atmospheric aerosols may play an important role. However, the ROS content in aerosols and their formation pathways are still largely unknown. Here, we have developed an online and offline ROS analyzer using a 2’,7’-dichlorofluorescin (DCFH) based assay. The sensitivity of the ROS analyzer was characterized using a suite of model organic compounds. The instrument detection limit determined as three times the noise is 1.3 nmol L−1 for offline analysis and 2 nmol m−3 of sampled air when the instrument is operated online at a fluorescence response time of approximately 8 min, while the offline method detection limit is 9 nmol L−1 to 13 nmol L−1. Potential interferences from gas phase O3 and NOx, matrix effects of particulate SO42− and NO3− were tested, but not observed. Fe3+ had no influence on the ROS signal while soluble Fe2+ reduced it if present at high concentrations in the extracts. Both online and offline methods were applied to identify the ROS content of different aerosol types, i.e., ambient aerosols as well as fresh and aged aerosols from wood combustion emissions. The stability of the ROS was assessed by comparing the ROS concentration measured by the same instrumentation online in-situ with offline measurements. We also analyzed the evolution of ROS in specific samples by conducting the analysis after storage times of up to four months. The ROS were observed to decay with increasing storage duration. From their decay behavior, ROS in secondary organic aerosol (SOA) can be separated into short- and long-lived fractions, with an average half-life of ~ 1.7 h and ~ 432 d, respectively. All these measurements showed consistently that, on average 60 ± 20 % of the ROS were very reactive and disappeared during the filter storage time. This demonstrates the importance of a fast online measurement of ROS.

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Organosulfates in atmospheric aerosols in Shanghai, China: seasonal and interannual variability, origin, and formation mechanisms

10.5194/acp-2020-784 ◽

2020 ◽

Author(s):

Yao Wang ◽

Yue Zhao ◽

Yuchen Wang ◽

Jian-Zhen Yu ◽

Jingyuan Shao ◽

...

Keyword(s):

Interannual Variability ◽

Atmospheric Aerosols ◽

Dominant Role ◽

Fine Particulate Matter ◽

Eastern China ◽

Anthropogenic Pollution ◽

Liquid Water Content ◽

Urban Site ◽

Formation Mechanisms ◽

Ambient Aerosols

Abstract. Organosulfates (OS) are ubiquitous in the atmosphere and serve as important tracers for secondary organic aerosols (SOA). Despite intense research over years, the abundance, origin, and formation mechanisms of OS in ambient aerosols, in particular in regions with severe anthropogenic pollution, are still not well understood. In this study, we collected filter samples of ambient fine particulate matter (PM2.5) over four seasons in both 2015/2016 and 2018/2019 at an urban site in Shanghai, China, and comprehensively characterized the OS species in these PM2.5 samples using a liquid chromatography coupled to a high resolution mass spectrometer (UPLC-ESI-QToF-MS). We find that while the concentration of organic aerosol (OA) decreased by 29 % in 2018/2019, compared to that in 2015/2016, the annually averaged concentrations of 35 quantified OS were similar in two years (65.5 ± 77.5 ng m−3 in 2015/2016 versus 59.4 ± 79.7 ng m−3 in 2018/2019), suggesting an increased contribution of SOA to OA in 2018/2019 than in 2015/2016. Isoprene- and monoterpene-derived OS are the two most abundant OS families, on average accounting for 36.3 % and 31.0 % of the quantified OS concentrations, respectively, suggesting an important contribution of biogenic emissions to the production of OS and SOA in Shanghai. The abundance of biogenic OS, particularly those arising from isoprene, exhibited strong seasonality (peaked in summer) but no significant interannual variability. In contrast, anthropogenic OS such as diesel-derived ones had little seasonal variability and declined obviously in 2018/2019 compared with that in 2015/2016. This reflects a significant change in precursor emissions in eastern China in recent years. The C2/C3 OS species that have both biogenic and anthropogenic origins averagely contributed to 19.0 % of the quantified OS, with C2H3O6S−, C3H5O5S−, and C3H5O6S− being the most abundant ones, together accounting for 76 % of C2/C3 OS concentrations. 2-Methyltetrol sulfate (2-MT-OS, C5H11O7S−) and monoterpene-derived C10H16NO7S− were the most abundant OS and nitrooxy-OS in summer, contributing to 31 % and 5 % of the quantified OS, respectively. The substantially larger concentration ratio of 2-MT-OS to 2-methylglyceric acid sulfate (2-MA-OS, C4H7O7S−) in summer (6.8–7.8) than in other seasons (0.31–0.78) implies that low-NOx oxidation pathways played a dominant role in isoprene-derived SOA formation in summer, while high-NOx reaction pathways were more important in other seasons. We further find that the production of OS was largely controlled by the level of Ox (Ox = O3 + NO2), namely, the photochemistry of OS precursors, in particular in summer, though sulfate concentration, aerosol acidity, as well as aerosol liquid water content (ALWC) that could affect the heterogeneous chemistry of reactive intermediates leading to OS formation also played a role. Our study provides valuable insights into the characteristics and mechanisms of OS formation in a typical Chinese megacity and implies that mitigation of Ox pollution can effectively reduce the production of OS and SOA in eastern China.

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Development of Certified Reference Materials for Diarrhetic Shellfish Poisoning Toxins, Part 2: Shellfish Matrix Materials

Journal of AOAC International ◽

10.5740/jaoacint.16-0152 ◽

2016 ◽

Vol 99 (5) ◽

pp. 1163-1172 ◽

Cited By ~ 8

Author(s):

Pearse McCarron ◽

Kelley L Reeves ◽

Sabrina D Giddings ◽

Daniel G Beach ◽

Michael A Quilliam

Keyword(s):

Reference Materials ◽

Matrix Effects ◽

Certified Reference Materials ◽

Standard Addition ◽

Tissue Homogenate ◽

Shellfish Poisoning ◽

Diarrhetic Shellfish Poisoning ◽

Preliminary Work ◽

Seafood Industry ◽

Human Illness

Abstract Okadaic acid (OA) and its analogs, dinophysistoxins-1 (DTX1) and -2 (DTX2) are lipophilic biotoxins produced by marine algae that can accumulate in shellfish and cause the human illness known as diarrhetic shellfish poisoning (DSP). Regulatory testing of shellfish is required to protect consumers and the seafood industry. Certified reference materials (CRMs) are essential for the development, validation, and quality control of analytical methods, and thus play an important role in toxin monitoring. This paper summarizes work on research and development of shellfish tissue reference materials for OA and DTXs. Preliminary work established the appropriate conditions for production of shellfish tissue CRMs for OA and DTXs. Source materials, including naturally incurred shellfish tissue and cultured algae, were screened for their DSP toxins. This preliminary work informed planning and production of a wet mussel (Mytilus edulis) tissue homogenate matrix CRM. The homogeneity and stability of the CRM were evaluated and found to be fit-for-purpose. Extraction and LC-tandem MS methods were developed to accurately certify the concentrations of OA, DTX1, and DTX2 using a combination of standard addition and matrix-matched calibration to compensate for matrix effects in electrospray ionization. The concentration of domoic acid was also certified. Uncertainties were assigned following standards and guidelines from the International Organization for Standardization. The presence of other toxins in the CRM was also assessed and information values are reported for OA and DTX acyl esters.

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A New Application of Continuous Wavelet Transform to Overlapping Chromatograms for the Quantitative Analysis of Amiloride Hydrochloride and Hydrochlorothiazide in Tablets by Ultra-Performance Liquid Chromatography

Journal of AOAC International ◽

10.5740/jaoacint.sge_dinc ◽

2012 ◽

Vol 95 (3) ◽

pp. 751-756 ◽

Cited By ~ 2

Author(s):

Erdal Dinç ◽

Eda Büker

Keyword(s):

Signal Processing ◽

Wavelet Transform ◽

Quantitative Analysis ◽

Continuous Wavelet Transform ◽

Standard Addition ◽

Ultra Performance Liquid Chromatography ◽

Continuous Wavelet ◽

Constant Flow Rate ◽

Acquity Uplc ◽

Amiloride Hydrochloride

Abstract A new application of continuous wavelet transform (CWT) to overlapping peaks in a chromatogram was developed for the quantitative analysis of amiloride hydrochloride (AML) and hydrochlorothiazide (HCT) in tablets. Chromatographic analysis was done by using an ACQUITY ultra-performance LC (UPLC) BEH C18 column (50 × 2.1 mm id, 1.7 μm particle size) and a mobile phase consisting of methanol–0.1 M acetic acid (21 + 79, v/v) at a constant flow rate of 0.3 mL/min with diode array detection at 274 nm. The overlapping chromatographic peaks of the calibration set consisting of AML and HCT mixtures were recorded rapidly by using an ACQUITY UPLC H-Class system. The overlapping UPLC data vectors of AML and HCT drugs and their samples were processed by CWT signal processing methods. The calibration graphs for AML and HCT were computed from the relationship between concentration and areas of chromatographic CWT peaks. The applicability and validity of the improved UPLC-CWT approaches were confirmed by recovery studies and the standard addition technique. The proposed UPLC-CWT methods were applied to the determination of AML and HCT in tablets. The experimental results indicated that the suggested UPLC-CWT signal processing provides accurate and precise results for industrial QC and quantitative evaluation of AML-HCT tablets.

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Development, characterization and first deployment of an improved online reactive oxygen species analyzer

Atmospheric Measurement Techniques ◽

10.5194/amt-11-65-2018 ◽

2018 ◽

Vol 11 (1) ◽

pp. 65-80 ◽

Cited By ~ 12

Author(s):

Jun Zhou ◽

Emily A. Bruns ◽

Peter Zotter ◽

Giulia Stefenelli ◽

André S. H. Prévôt ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Detection Limit ◽

Atmospheric Aerosols ◽

Half Life ◽

Matrix Effects ◽

Reactive Oxygen ◽

Oxygen Species ◽

Wood Combustion ◽

Storage Duration ◽

High Concentrations

Abstract. Inhalation of atmospheric particles is linked to human diseases. Reactive oxygen species (ROS) present in these atmospheric aerosols may play an important role. However, the ROS content in aerosols and their formation pathways are still largely unknown. Here, we have developed an online and offline ROS analyzer using a 2′,7′-dichlorofluorescin (DCFH) based assay. The ROS analyzer was calibrated with H2O2 and its sensitivity was characterized using a suite of model organic compounds. The instrument detection limit determined as 3 times the noise is 1.3 nmol L−1 for offline analysis and 2 nmol m−3 of sampled air when the instrument is operated online at a fluorescence response time of approximately 8 min, while the offline method detection limit is 18 nmol L−1. Potential interferences from gas-phase O3 and NO2 as well as matrix effects of particulate SO42− and NO3− were tested, but not observed. Fe3+ had no influence on the ROS signal, while soluble Fe2+ reduced it if present at high concentrations in the extracts. Both online and offline methods were applied to identify the ROS content of different aerosol types, i.e., ambient aerosols as well as fresh and aged aerosols from wood combustion emissions. The stability of the ROS was assessed by comparing the ROS concentration measured by the same instrumentation online in situ with offline measurements. We also analyzed the evolution of ROS in specific samples by conducting the analysis after storage times of up to 4 months. The ROS were observed to decay with increasing storage duration. From their decay behavior, ROS in secondary organic aerosol (SOA) can be separated into short- and long-lived fractions. The half-life of the short-lived fraction was 1.7 ± 0.4 h, while the half-life of the long-lived fraction could not be determined with our uncertainties. All these measurements showed consistently that on average 60 ± 20 % of the ROS were very reactive and disappeared during the filter storage time. This demonstrates the importance of a fast online measurement of ROS.

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A Metabolomic Strategy to Screen the Prototype Components and Metabolites ofShuang-Huang-Lian Injectionin Human Serum by Ultra Performance Liquid Chromatography Coupled with Quadrupole Time-of-Flight Mass Spectrometry

Journal of Analytical Methods in Chemistry ◽

10.1155/2014/241505 ◽

2014 ◽

Vol 2014 ◽

pp. 1-12 ◽

Cited By ~ 4

Author(s):

Mingxing Guo ◽

Baosheng Zhao ◽

Haiyu Liu ◽

Li Zhang ◽

Long Peng ◽

...

Keyword(s):

Human Serum ◽

Human Body ◽

Matrix Effects ◽

Ultra Performance Liquid Chromatography ◽

Acute Respiratory Tract Infection ◽

Chemical Compositions ◽

Drug Induced ◽

Flight Mass Spectrometry ◽

Chinese Patent ◽

Metabolic Reactions

Shuang-huang-lian injection(SHLI) is a famous Chinese patent medicine, which has been wildly used in clinic to treat acute respiratory tract infection, pneumonia, influenza, and so forth. Despite the widespread clinical application, the prototype components and metabolites ofSHLIhave not been fully elucidated, especially in human body. To discover and screen the constituents or metabolites of Chinese medicine in biofluids tends to be more and more difficult due to the complexity of chemical compositions, metabolic reactions and matrix effects. In this work, a metabolomic strategy to comprehensively elucidate the prototype components and metabolites ofSHLIin human serum conducted by UPLC-Q-TOF/MS was developed. Orthogonal partial least squared discriminant analysis (OPLS-DA) was applied to distinguish the exogenous, namely, drug-induced constituents, from endogenous in human serum. In the S-plot, 35 drug-induced constituents were found, including 23 prototype compounds and 12 metabolites which indicated thatSHLIin human body mainly caused phase II metabolite reactions. It was concluded that the metabolomic strategy for identification of herbal constituents and metabolites in biological samples was successfully developed. This identification and structural elucidation of the chemical compounds provided essential data for further pharmacological and pharmacokinetics study ofSHLI.

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A new approach for retrieving the UV–vis optical properties of ambient aerosols

Atmospheric Measurement Techniques ◽

10.5194/amt-9-3477-2016 ◽

2016 ◽

Vol 9 (8) ◽

pp. 3477-3490 ◽

Cited By ~ 17

Author(s):

Nir Bluvshtein ◽

J. Michel Flores ◽

Lior Segev ◽

Yinon Rudich

Keyword(s):

Optical Properties ◽

Atmospheric Aerosols ◽

Radiative Forcing ◽

Complex Refractive Index ◽

Single Scattering ◽

Aerosol Size Distribution ◽

Distribution Data ◽

Ambient Aerosols ◽

New Approach ◽

Effective Radiative Forcing

Abstract. Atmospheric aerosols play an important part in the Earth's energy budget by scattering and absorbing incoming solar and outgoing terrestrial radiation. To quantify the effective radiative forcing due to aerosol–radiation interactions, researchers must obtain a detailed understanding of the spectrally dependent intensive and extensive optical properties of different aerosol types. Our new approach retrieves the optical coefficients and the single-scattering albedo of the total aerosol population over 300 to 650 nm wavelength, using extinction measurements from a broadband cavity-enhanced spectrometer at 315 to 345 nm and 390 to 420 nm, extinction and absorption measurements at 404 nm from a photoacoustic cell coupled to a cavity ring-down spectrometer, and scattering measurements from a three-wavelength integrating nephelometer. By combining these measurements with aerosol size distribution data, we retrieved the time- and wavelength-dependent effective complex refractive index of the aerosols. Retrieval simulations and laboratory measurements of brown carbon proxies showed low absolute errors and good agreement with expected and reported values. Finally, we implemented this new broadband method to achieve continuous spectral- and time-dependent monitoring of ambient aerosol population, including, for the first time, extinction measurements using cavity-enhanced spectrometry in the 315 to 345 nm UV range, in which significant light absorption may occur.

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An Accurate and Effective Method for Measuring Osimertinib by UPLC-TOF-MS and Its Pharmacokinetic Study in Rats

Molecules ◽

10.3390/molecules23112894 ◽

2018 ◽

Vol 23 (11) ◽

pp. 2894 ◽

Cited By ~ 6

Author(s):

Song-Tao Dong ◽

Ying Li ◽

Hao-Tian Yang ◽

Yin Wu ◽

Ya-Jing Li ◽

...

Keyword(s):

Matrix Effects ◽

Internal Standard ◽

Ultra Performance Liquid Chromatography ◽

Rat Plasma ◽

Analysis Method ◽

T790m Mutation ◽

Flight Mass Spectrometry ◽

Relative Standard ◽

New Generation ◽

Tof Ms

Osimertinib, a new-generation inhibitor of the epidermal growth factor, has been used for the clinical treatment of advanced T790M mutation-positive tumors. In this research, an original analysis method was established for the quantification of osimertinib by ultra-performance liquid chromatography with time of flight mass spectrometry (UPLC-TOF-MS) in rat plasma. After protein precipitation with acetonitrile and sorafinib (internal standard, IS), they were chromatographed through a Waters XTerra MS C18 column. The mobile phase was acetonitrile and water (including 0.1% ammonia). The relative standard deviation (RSD) of the intra- and inter-day results ranged from 5.38 to 9.76% and from 6.02 to 9.46%, respectively, and the extraction recovery and matrix effects were calculated to range from 84.31 to 96.14% and from 91.46 to 97.18%, respectively. The results illustrated that the analysis method had sufficient specificity, accuracy and precision. Meanwhile, the UPLC-TOF-MS method for osimertinib was successfully applied into the pharmacokinetics of SD rats.

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