Organosulfates in atmospheric aerosol: synthesis and quantitative analysis of PM 2.5 from Xi'an, northwestern China
Abstract. The sources, formation mechanism and amount of organosulfates (OS) in
atmospheric aerosol are not yet well understood, partly due to the lack of
authentic standards for quantification. In this study, we report an improved
robust procedure for the synthesis of organosulfates with different
functional groups. Nine authentic organosulfate standards were synthesized
and four standards (benzyl sulfate, phenyl sulfate, glycolic acid sulfate,
and hydroxyacetone sulfate) were used to quantify their ambient
concentrations. The authentic standards and ambient aerosol samples were
analyzed using an optimized ultra performance liquid
chromatography–electrospray ionization-tandem mass spectrometric method
(UPLC–ESI–MS/MS). The recovery ranged from 80.4 to 93.2 %, the limits
of detection and limits of quantification obtained were 1.1–16.7 and
3.4–55.6 pg m −3 , respectively. Measurements of ambient aerosol
particle samples collected in winter 2013/2014 in urban Xi'an, northwestern
China, show that glycolic acid sulfate (77.3  ±  49.2 ng m −3) is
the most abundant species of the identified organosulfates followed by
hydroxyacetone sulfate (1.3  ±  0.5 ng m −3) , phenyl sulfate
(0.14  ±  0.09 ng m −3) , and benzyl sulfate
(0.04  ±  0.01 ng m −3) . Except for hydroxyacetone sulfate, which
seems to form mainly from biogenic emissions in this region, the
organosulfates quantified during winter in Xi'an show an increasing trend
with an increase in the mass concentrations of organic carbon indicating
their anthropogenic origin.