Probing sulphur clusters in a microfluidic electrochemical cell with synchrotron-based photoionization mass spectrometry

Abstract

<p> <italic>In operando</italic> synchrotron analysis captures sulphur clusters’ formation and determines their ionization energies in a low-dielectric lithium sulfide electrolyte.</p>

Studying Interfacial Dark Reactions of Glyoxal and Hydrogen Peroxide Using Vacuum Ultraviolet Single Photon Ionization Mass Spectrometry

“…The Si frame was irreversibly bonded to the PDMS block after oxygen plasma treatment. After assembling the SALVI cells, two apertures of 2 µm in diameter and 100 µm apart (Figure 1b) were milled on the SiN membrane above the center of the channel using scanning electron microscopy with the focused ion beam (SEM-FIB) to allow evaporation of liquids in vacuum [19,20,25]. More details about cell design and fabrications were described in our previous studies [17,18].…”

“…To enable chemical analysis of the liquid-vacuum interface and use that to approximate the a-l interface, we developed a vacuum applicable microfluidic reactor, namely, the System for Analysis at the Liquid Vacuum Interface (SALVI) [17,18]. Recent work has shown that combining SALVI with VUV SPI-MS makes it possible to probe the aqueous surface reaction products in high vacuum and provides unique insights into the a-l reaction mechanisms [19,20]. In the atmosphere, glyoxal molecules can go through hydration then follow with oxidation to form glyoxylic acid, formic acid, and oxalic acid.…”

New Insights into Secondary Organic Aerosol Formation at the Air–Liquid Interface

“…[9][10] Nevertheless, recent studies show that integrating a vacuum compatible microreactor, namely system for analysis at the liquid − vacuum interface (SALVI) [11][12][13][14] and VUV SPI-MS, makes it possible to study aqueous reactions in a dynamic environment. [15][16] We present the combination of tunable synchrotron VUV SPI-MS and SALVI microreactor to observe molecular intermediates and products of glyoxal photooxidation at the a − l interface approximated by the liquid − vacuum interface in this work. [17][18] This in situ study of a − l interfacial SOA formation from photochemical oxidation using liquid VUV SPI-MS is the first to the best of our knowledge.…”

“…It has been widely used in complex chemical systems to detect organic molecules with fewer fragments compared to traditional harsh ionization methods, such as electron impact, and allows for determination of ionization energies (IEs) which aids in chemical identification and isomer selectivity . Coupling VUV radiation with mass spectrometry is regarded as a traditional gas-phase and gas–solid interfacial experiment, because measurements must be performed under high vacuum. , Nevertheless, recent studies show that integrating a vacuum compatible microreactor, namely, system for analysis at the liquid–vacuum interface (SALVI) − and VUV SPI-MS, makes it possible to study aqueous reactions in a dynamic environment. , …”

“…Figure shows the schematic of the experimental setup and types of measurements using in situ VUV SPI-MS. More details were reported recently , and in the Supporting Information (SI). Briefly, liquid consisting of glyoxal and hydrogen peroxide was sealed in between two silicon nitride membranes in the microchannel of SALVI (Figure b), and the liquid was withheld by its surface tension across the aperture in high vacuum. − Two micrometer-sized apertures were milled to allow liquid evaporation, making it possible to detect evaporated molecules during experiments in high vacuum (Figure c,d).…”