Determination of atmospheric organosulfates using HILIC chromatography with MS detection

Measurements of organosulfates in ambient aerosols provide insight to the extent of secondary organic aerosol (SOA) formation from mixtures of biogenic gases and anthropogenic pollutants. Organosulfates have, however, proved analytically challenging to quantify, due to lack of authentic standards an...

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Main Authors: A. P. S. Hettiyadura, E. A. Stone, S. Kundu, Z. Baker, E. Geddes, K. Richards, T. Humphry
Format: Article
Language:English
Published: Copernicus Publications 2015-06-01
Series:Atmospheric Measurement Techniques
Online Access:http://www.atmos-meas-tech.net/8/2347/2015/amt-8-2347-2015.pdf
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author A. P. S. Hettiyadura
E. A. Stone
S. Kundu
Z. Baker
E. Geddes
K. Richards
T. Humphry
author_facet A. P. S. Hettiyadura
E. A. Stone
S. Kundu
Z. Baker
E. Geddes
K. Richards
T. Humphry
author_sort A. P. S. Hettiyadura
collection DOAJ
description Measurements of organosulfates in ambient aerosols provide insight to the extent of secondary organic aerosol (SOA) formation from mixtures of biogenic gases and anthropogenic pollutants. Organosulfates have, however, proved analytically challenging to quantify, due to lack of authentic standards and the complex sample matrix in which organosulfates are observed. This study presents a sensitive and accurate new analytical method for the quantification of organosulfates based upon ultra-performance liquid chromatography (UPLC) with negative electrospray ionization mass spectrometry (MS) with the aid of synthesized organosulfate standards. The separation is based upon hydrophilic interaction liquid chromatography (HILIC) with an amide stationary phase that provides excellent retention of carboxy-organosulfates and isoprene-derived organosulfates. The method is validated using six model compounds: methyl sulfate, ethyl sulfate, benzyl sulfate, hydroxyacetone sulfate, lactic acid sulfate and glycolic acid sulfate. A straightforward protocol for synthesis of highly pure organosulfate potassium salts for use as quantification standards is presented. This method is used to evaluate the efficiency and precision of two methods of ambient PM<sub>2.5</sub> sample extraction. Spike recoveries averaged 98 ± 8% for extraction by ultra-sonication and 98 ± 10% for extraction by rotary shaking. Ultra-sonication was determined to be a better method due to its higher precision compared to rotary shaking. Analysis of ambient PM<sub>2.5</sub> samples collected on 10–11 July 2013 in Centreville, AL, USA during the Southeast Atmosphere Study (SAS) confirms the presence of hydroxyacetone sulfate in ambient aerosol for the first time. Lactic acid sulfate was the most abundant compound measured (9.6–19 ng m<sup>−3</sup>), followed by glycolic acid sulfate (8–14 ng m<sup>−3</sup>) and hydroxyacetone sulfate (2.7–5.8 ng m<sup>−3</sup>). Trace amounts of methyl sulfate were detected, while ethyl sulfate and benzyl sulfate were not. Application of this HILIC separation method to ambient aerosol samples further demonstrates its utility in resolving additional biogenic organosulfates.
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spelling doaj.art-2181fa8338a440dd94447cc8425fb4f52022-12-21T20:30:06ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482015-06-01862347235810.5194/amt-8-2347-2015Determination of atmospheric organosulfates using HILIC chromatography with MS detectionA. P. S. Hettiyadura0E. A. Stone1S. Kundu2Z. Baker3E. Geddes4K. Richards5T. Humphry6Department of Chemistry, Chemistry Building, University of Iowa, Iowa City, IA 52242, USADepartment of Chemistry, Chemistry Building, University of Iowa, Iowa City, IA 52242, USADepartment of Chemistry, Chemistry Building, University of Iowa, Iowa City, IA 52242, USADepartment of Chemistry, Chemistry Building, University of Iowa, Iowa City, IA 52242, USAChemistry Department, Truman State University, Kirksville, MO 63501, USAChemistry Department, Truman State University, Kirksville, MO 63501, USAChemistry Department, Truman State University, Kirksville, MO 63501, USAMeasurements of organosulfates in ambient aerosols provide insight to the extent of secondary organic aerosol (SOA) formation from mixtures of biogenic gases and anthropogenic pollutants. Organosulfates have, however, proved analytically challenging to quantify, due to lack of authentic standards and the complex sample matrix in which organosulfates are observed. This study presents a sensitive and accurate new analytical method for the quantification of organosulfates based upon ultra-performance liquid chromatography (UPLC) with negative electrospray ionization mass spectrometry (MS) with the aid of synthesized organosulfate standards. The separation is based upon hydrophilic interaction liquid chromatography (HILIC) with an amide stationary phase that provides excellent retention of carboxy-organosulfates and isoprene-derived organosulfates. The method is validated using six model compounds: methyl sulfate, ethyl sulfate, benzyl sulfate, hydroxyacetone sulfate, lactic acid sulfate and glycolic acid sulfate. A straightforward protocol for synthesis of highly pure organosulfate potassium salts for use as quantification standards is presented. This method is used to evaluate the efficiency and precision of two methods of ambient PM<sub>2.5</sub> sample extraction. Spike recoveries averaged 98 ± 8% for extraction by ultra-sonication and 98 ± 10% for extraction by rotary shaking. Ultra-sonication was determined to be a better method due to its higher precision compared to rotary shaking. Analysis of ambient PM<sub>2.5</sub> samples collected on 10–11 July 2013 in Centreville, AL, USA during the Southeast Atmosphere Study (SAS) confirms the presence of hydroxyacetone sulfate in ambient aerosol for the first time. Lactic acid sulfate was the most abundant compound measured (9.6–19 ng m<sup>−3</sup>), followed by glycolic acid sulfate (8–14 ng m<sup>−3</sup>) and hydroxyacetone sulfate (2.7–5.8 ng m<sup>−3</sup>). Trace amounts of methyl sulfate were detected, while ethyl sulfate and benzyl sulfate were not. Application of this HILIC separation method to ambient aerosol samples further demonstrates its utility in resolving additional biogenic organosulfates.http://www.atmos-meas-tech.net/8/2347/2015/amt-8-2347-2015.pdf
spellingShingle A. P. S. Hettiyadura
E. A. Stone
S. Kundu
Z. Baker
E. Geddes
K. Richards
T. Humphry
Determination of atmospheric organosulfates using HILIC chromatography with MS detection
Atmospheric Measurement Techniques
title Determination of atmospheric organosulfates using HILIC chromatography with MS detection
title_full Determination of atmospheric organosulfates using HILIC chromatography with MS detection
title_fullStr Determination of atmospheric organosulfates using HILIC chromatography with MS detection
title_full_unstemmed Determination of atmospheric organosulfates using HILIC chromatography with MS detection
title_short Determination of atmospheric organosulfates using HILIC chromatography with MS detection
title_sort determination of atmospheric organosulfates using hilic chromatography with ms detection
url http://www.atmos-meas-tech.net/8/2347/2015/amt-8-2347-2015.pdf
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