Characterization of electrochemical flow cell configurations with implemented disposable electrodes for the direct coupling to mass spectrometry

Abstract

The characterization of the redox behavior of analytes is a very important aspect for many applications. Pure electrochemical approaches can provide useful information on electroactive species, but are of limited use regarding the identification of generated species. The hyphenation of electrochemistry and mass spectrometry (EC-MS) is a powerful method to investigate redox systems. In the present work, we show a simple approach to on-line EC-MS based on the application of electrochemical flow cells with implemented disposable electrodes. They are connected to electrospray ionization mass spectrometry (ESI-MS) via fused silica capillary tubing. The modularity of the flow cells offers a high flexibility of experimental setup and settings, so that a fast detection of oxidation or reduction products can be achieved. The usage of disposable electrodes guarantees a high level of quality assurance for EC-MS measurements.

Investigation of the electrochemical behavior of cysteine by hyphenation of electrochemistry and mass spectrometry

“…Cysteine's electrochemical conversion in EC-MS measurements was conducted using a modified flow cell (Metrohm DropSens, Spain) [18] for SPEs. A µStat 200 potentiostat (Metrohm DropSens, Spain) was used for controlling the potential.…”

Investigation of the Electrooxidation of Thymine on Screen-Printed Carbon Electrodes by Hyphenation of Electrochemistry and Mass Spectrometry

“…As illustrated in Figure 1A, EC-MS measurements were carried out by coupling an electrochemical flow cell with integrated SPCE (DRP-FLWCL, DropSens) to MS via a fused silica capillary (50 μm × 21 cm, Polymicro Technologies, AZ, USA), which was installed in the cell using a modified PEEK fitting and sleeve as described previously. 18 The solutions were transported to the detector by a microinjection syringe pump (World Precision Instruments, Sarasota, FL, USA) equipped with a 1 mL glass syringe (Hamilton Company, Reno, NV, USA) at a flow rate of 16 μL min −1 , corresponding to a fast transfer time of 1−2 s between generation at the electrode and detection in MS (experimentally determined by using ferrocene methanol as model system at an oxidation potential of 0.5 V). Due to this fast detection of products, the real-time response of the product composition while scanning a potential ramp from 0 to 2 V at 10 mV s −1 could be recorded.…”

“…EC-MS and, in particular, electrochemical real-time mass spectrometry (EC-RTMS) measurements are characterized by a fast detection of electrogenerated species and allow for the investigation of reactive intermediates and dynamic processes such as the determination of oxidation products under potential sweep conditions . By establishing flow cell configurations with very low dead volumes, very fast transfer times to MS can be achieved . However, if a separation step is added, additional information such as polarity of occurring structures can be obtained and fragmentation of respective peaks in MS can be investigated .…”

“…17 By establishing flow cell configurations with very low dead volumes, very fast transfer times to MS can be achieved. 18 However, if a separation step is added, additional information such as polarity of occurring structures can be obtained and fragmentation of respective peaks in MS can be investigated. 19 Using screen-printed platforms for oxidation offers different advantages.…”