Quantitative Determination of Hydroxymethanesulfonate (HMS) Using Ion Chromatography and UHPLC-LTQ-Orbitrap Mass Spectrometry: A Missing Source of Sulfur during Haze Episodes in Beijing

Abstract

Hydroxymethanesulfonate (HMS), the product of HSO 3 − and SO 3 2− reacting with dissolved formaldehyde in fog, cloud, and aerosol liquid water, has been suggested to be an important source of particulate sulfur during haze events. However, there have been limited studies of high concentrations of HMS in atmospheric aerosol. We report here two feasible analytical methods for the identification of HMS using ion chromatography and UHPLC-LTQ-Orbitrap mass spectrometry. The concentrations of HMS in fine particles in wintertime Beijing ranged from below the detection limit to 7.3 μg m −3 (with an average at 2.0 ± 2.1 μg m −3 ). Increased concentrations of HMS and sulfate were associated with the occurrence of fog. The results reveal that HMS may be a potential S(IV) reservoir and an effective tracer of aqueous-phase chemistry. The atmospheric aqueous-phase chemistry promoted the rapid conversion of S(IV) under haze−fog conditions. The kinetic modeling results suggest that the aqueous pH should be taken into account when exploring the mechanism of HMS formation in atmospheric sulfur chemistry.

Global modeling of heterogeneous hydroxymethanesulfonate chemistry

“…3 ), the most abundant hydroxyalkylsulfonate species commonly found in the atmosphere, have been detected in winter in Beijing, China using an aerosol mass spectrometer by Song et al (2019a), using an improved ion chromatography method by Ma et al (2020), and using a UHPLC-LTQ-Orbitrap mass spectrometry by Wei et al (2020). The mass spectrometry quantification of HMS in ambient aerosols may be subject to the interference of other inorganic and organic sulfur compounds, as suggested by Dovrou et al (2019).…”

Online Liquid Chromatography and FT-ICR MS Enable Advanced Separation and Profiling of Organosulfates in Dissolved Organic Matter

“…Organic sulfur compounds are present as S–H, C–S, CS, SO, and −SO 2 – groups. These compounds are frequently studied in the atmosphere such as ambient aerosols, rainwater, snow, and fogwater by atmospheric chemists . In addition, sulfur can also be present in water samples in numerous forms and it would be of great interest to obtain further insight into their possible structures via tandem mass spectrometry (MS n ).…”

Hydroxymethanesulfonate (HMS) Formation during Summertime Fog in an Arctic Oil Field

“…32,33 In summertime Atlanta, GA, 10−15% of measured individual particles contained HMS, which often coexisted in the same particles as carboxylic acids and other oxidized organic compounds indicative of aqueous processing. 41,42 Recent studies [32][33][34][35]43 proposed that the HMS concentration can reach significant levels in China during winter haze and may be misidentified as sulfate. HMS formation may explain high particulate sulfur concentrations in Beijing, 43 wintertime concentrations of up to 7.3 μg/m 3 .…”

“…HMS formation may explain high particulate sulfur concentrations in Beijing, 43 wintertime concentrations of up to 7.3 μg/m 3 . 35 Song et al 32 showed that Beijing sulfate model predictions improve through the inclusion of HMS formation. Moch et al 34 and Song et al 44 recently presented observational and modeling evidence of the global presence of HMS.…”

“…HMS has been measured in fogwater, ,− precipitation, − and aerosol particles. − HMS production is favored within fog and cloud droplets, compared to aerosol, in part due to the increased pH. In particular, single-particle mass spectrometry provides HMS identification within individual atmospheric particles by detection of its molecular ion [ m / z −111 (HOCH 2 SO 3 – )]. − Whiteaker et al first observed individual particles containing HMS during fog events in Bakersfield, CA.…”