Technology

Fast time response

In the experiment, Pt is used to electrolyze water to hydrogen and oxygen using electrochemistry. Sending a carbon monoxide (CO) pulse through the membrane microchip, the Pt electrode is poisoned. On the right, a representation of the mass spectrometry (MS) data versus common potential is shown. This type of plot is commonly used in differential electrochemical mass spectrometry (DEMS), online electrochemical mass spectrometry (OLEMS), or membrane inlet mass spectrometry (MIMS) graphs. In the plot on the left, time resolution and dependency is preserved, whereas on the right, time information is lost.

Figure 1. H2 evolution and CO stripping experiments using a 5 mm polycrystalline Pt electrode in 1M HClO4. Potential sweeps are carried out at 20 mV/s. a) Different signals from the mass spectrometer corresponding to H2 (m/z=2), He (m/z=4), CO (m/z=28) and CO2 (m/z=44) along with the potential and current density as a function of time. b) MS signal as a function of applied voltage and CVs corresponding to the colored sweeps in a).

The system can measure composition changes of volatile species with a time resolution down to 0.1 seconds. This allows to effortlessly produce EC-MS plots, as shown in Figure 1, with EC and MS signal plotted against common time (a) and against applied potential (b) (Read more on the experiment in Example EC-MS section). The software integration takes care of synchronization, so there is no need to manually (and somewhat inaccurately) record the time-zero when the EC technique is started with respect to the MS signal. For more information on software integration, see Software section.

D. B. Trimarco et al., Enabling real-time detection of electrochemical desorption phenomena with sub-monolayer sensitivity. Electrochim. Acta. 268, 520–530 (2018).