Hiden Analytical Europe recently hosted a technical DEMS/OEMS Workshop in Garching, Munich, organised by Sachin Menon, Sebastian Hentschel and Jürgen from Hiden Analytical Europe. Jim also travelled from the UK to lead the live demonstration of the device and support the workshop.
For researchers working in electrochemistry, battery development, fuel cell studies, electrocatalysis, corrosion research and reaction monitoring, real-time gas analysis can provide valuable insight into gases and volatile species produced during electrochemical processes.
Techniques such as Differential Electrochemical Mass Spectrometry (DEMS) and Online Electrochemical Mass Spectrometry (OEMS) help researchers connect electrochemical behaviour with gas evolution, product formation and reaction pathways.
Key Takeaways
The DEMS/OEMS Workshop in Garching provided a technical overview of DEMS and OEMS for electrochemistry, with a focus on instrumentation, software integration and practical application discussion.
DEMS combines electrochemical half-cell experimentation with mass spectrometry and allows in situ, mass-resolved determination of gaseous or volatile electrochemical reactants, reaction intermediates and products in real time.
The HPR-40 DEMS is a laboratory mass spectrometry system developed for in situ, real-time analysis of gases and volatile species in electrochemical research.
The HPR-20 OEMS is configured for continuous analysis of evolved gases and vapours in electrochemistry as a function of applied potential on the real-time scale.
What the DEMS/OEMS Workshop Covered
The technical workshop in Garching was structured around both instrumentation and application insight. After a welcome and introduction, the session included a company presentation from Hiden Analytical, followed by a presentation on the HPR-40 DEMS system with the new ECL Series cells.
The workshop also covered DEMS software and integration options with external devices, helping attendees understand how mass spectrometry data can be aligned with electrochemical measurements and experimental workflows. The Q&A and application workshop sections provided time for discussion around specific research requirements, experimental challenges and application needs.
Rather than focusing only on instrumentation, the workshop addressed how DEMS and OEMS systems can support real electrochemical research questions.
Why DEMS and OEMS Matter in Electrochemistry
Electrochemical reactions are often dynamic and multi-step. A current response or voltage profile can show that a reaction is taking place, but it does not always identify which gases, vapours or volatile products are being formed.
This is where electrochemistry mass spectrometry becomes valuable. By combining electrochemical control with mass spectrometric detection, researchers can investigate gas evolution, product selectivity, reaction intermediates and changes that occur as a function of applied potential.
Hiden’s DEMS application page describes DEMS as an analytical technique that combines electrochemical half-cell experimentation with mass spectrometry. It allows in situ mass-resolved determination of gaseous or volatile electrochemical reactants, reaction intermediates and products in real time.
Understanding DEMS: Differential Electrochemical Mass Spectrometry
DEMS, or Differential Electrochemical Mass Spectrometry, is an analytical technique that combines electrochemical half-cell experimentation with mass spectrometry.
According to Hiden Analytical, DEMS allows the in situ mass-resolved determination of gaseous or volatile electrochemical reactants, reaction intermediates and products in real time. The experimental setup consists of an electrochemical half-cell, a membrane interface and a vacuum system including a quadrupole mass spectrometer.
In practical terms, DEMS helps researchers investigate questions such as:
- Which gaseous or volatile products are generated during an electrochemical reaction?
- How does product formation change with applied potential?
- Can reaction intermediates be detected in real time?
- How do catalysts, electrodes or electrolyte conditions affect product selectivity?
- Are side reactions or degradation processes producing detectable gas species?
The HPR-40 DEMS is developed for in situ, real-time analysis of gases and volatile species in electrochemical research. Hiden lists applications including fuel cell diagnostics, CO₂ reduction, catalyst evaluation, corrosion studies, oxygen reduction reaction (ORR) and battery research.
HPR-40 DEMS and ECL Series Cells
A central focus of the workshop was the HPR-40 DEMS system with the new ECL Series cells.
The HPR-40 DEMS is described by Hiden Analytical as a laboratory mass spectrometry system for real-time gas analysis in advanced energy and electrocatalytic research. It is designed to provide immediate data on reaction pathways and product selectivity in electrochemical research.
The system is modular and compatible with a range of electrochemical cells and probes. Hiden’s ECL Series includes:
ECL-Static
The ECL-Static cell features a vitreous carbon working electrode. Hiden describes it as user-friendly and versatile, with a configurable static or flow cell design and a customisable working surface that can be coated by the user.
ECL-Insight
The ECL-Insight uses a sputter-compatible membrane that can be user-coated to suit a given experiment. Hiden describes the ECL-Insight as offering a direct electrode-to-MS connection, rapid scan capability up to 100 mV/s, high sensitivity, high-current capability up to 100 mA/cm² and a dual-chamber design to help prevent cross-contamination and cathode poisoning from anode byproducts.
ECL-Probe
The ECL-Probe enables direct dissolved gas analysis in standard or custom electrochemical cells. Hiden notes that its non-metallic design allows it to be fully immersed in electrolyte without interacting with the electrochemistry.
Together, these ECL Series options support different approaches to electrochemical gas analysis, including catalyst studies, dissolved gas analysis, custom cell configurations and direct coupling between electrochemical experiments and mass spectrometric detection.
Understanding OEMS: Online Electrochemical Mass Spectrometry
OEMS, or Online Electrochemical Mass Spectrometry, is used for online monitoring of evolved gases and vapours in electrochemical systems.
The HPR-20 OEMS is described by Hiden Analytical as a gas analysis system configured for continuous analysis of evolved gases and vapours in electrochemistry as a function of applied potential on the real-time scale.
The system uses an ultralow-flow real-time sampling capillary for connection to headspace sampling and/or electrochemical cells. Hiden’s QIC ULF quartz-lined ultra-low-flow sampling inlet operates at up to 200°C and provides fast response times of less than three seconds for most common gases and vapours, including water vapour.
Hiden lists HPR-20 OEMS applications including DEMS, electrocatalyst studies, fuel cell studies, cathode studies, CO₂ reduction, lithium-ion battery research, nitrogen reduction and green hydrogen.
HPR-20 OEMS for Continuous Evolved Gas and Vapour Analysis
The HPR-20 OEMS supports continuous online analysis for electrochemistry applications where evolved gases and vapours need to be monitored in real time.
Hiden lists key HPR-20 OEMS features including:
- multiple gas and vapour analysis with a 0–300 amu mass range option
- sample flow rate options from 12 µl/min to 16 ml/min
- continuous sampling heated capillary inlet
- real-time multispecies analysis from 100 ppb to 100%
- response times as fast as 300 ms
- fast data acquisition up to 1000 measurements per second
- soft ionisation for reduced spectral fragmentation and simplified data interpretation
- broad sampling accessory options
- custom-designed interfaces for OEMS applications
For electrochemical research, this makes OEMS useful where gases and vapours need to be monitored continuously during applied potential changes, cycling studies or longer-duration experiments.
Software, Integration and Practical Application Support
The workshop also included a session on DEMS software and integration options with external devices.
This is an important part of electrochemical mass spectrometry because useful DEMS and OEMS workflows often depend on synchronising electrochemical and mass spectrometry data. A typical setup may involve a potentiostat or electrochemical workstation, electrochemical cell, mass spectrometer, sampling interface and software for data acquisition and analysis.
For the HPR-40 DEMS, Hiden states that supplied cables enable straightforward integration with an electrochemical workstation, supporting data synchronisation within a single software package. The QGA software allows potential, current, time and mass spectrometer signals to be plotted in real time.
The HPR-40 DEMS is supplied with MASsoft Professional, QGAsoft and EGAsoft software. MASsoft Professional provides instrument control via USB 2.0, RS232 or Ethernet, with I/O for data output and for reading external device data for integration and display with mass spectrometer data. QGAsoft provides real-time continuous quantitative gas and vapour analysis of up to 32 species, with concentration measurement from 0.1 ppm to 100%.
The HPR-20 OEMS is supplied with QGAsoft and MASsoft Professional, supporting real-time quantitative gas and vapour analysis and external device data integration.
Supporting Battery, Fuel Cell and Catalysis Research
DEMS and OEMS are relevant to many areas of electrochemical research.
In battery research, real-time gas analysis can support studies of gas evolution and processes linked to electrochemical operation. Hiden lists battery research as an application area for HPR-40 DEMS and lithium-ion battery research as an application area for HPR-20 OEMS.
In fuel cell research, DEMS and OEMS can support studies of evolved gases, reaction products and catalyst behaviour. Hiden lists fuel cell diagnostics for HPR-40 DEMS and fuel cell studies for HPR-20 OEMS.
In catalysis and electrocatalysis research, these techniques help researchers connect electrochemical conditions with gas-phase and volatile reaction products. Hiden lists catalyst evaluation and electrocatalyst studies among relevant application areas for the HPR-40 DEMS and HPR-20 OEMS systems.
The Garching workshop provided a technical setting to explore these themes, with a focus on practical instrumentation, software integration and application-specific discussion.
FAQ: DEMS and OEMS for Electrochemistry
What is DEMS in electrochemistry?
DEMS stands for Differential Electrochemical Mass Spectrometry. Hiden Analytical describes DEMS as an analytical technique that combines electrochemical half-cell experimentation with mass spectrometry, allowing in situ mass-resolved determination of gaseous or volatile electrochemical reactants, reaction intermediates and products in real time.
What is the HPR-40 DEMS used for?
The HPR-40 DEMS is used for in situ, real-time analysis of gases and volatile species in electrochemical research. Hiden lists applications including fuel cell diagnostics, CO₂ reduction, catalyst evaluation, corrosion studies, oxygen reduction reaction and battery research.
What is OEMS in electrochemistry?
OEMS refers to Online Electrochemical Mass Spectrometry. Hiden’s HPR-20 OEMS is configured for continuous analysis of evolved gases and vapours in electrochemistry as a function of applied potential on the real-time scale.
What is the HPR-20 OEMS used for?
The HPR-20 OEMS is used for continuous analysis of evolved gases and vapours in electrochemistry. Hiden lists applications including DEMS, electrocatalyst studies, fuel cell studies, cathode studies, CO₂ reduction, lithium-ion battery research, nitrogen reduction and green hydrogen.
What are ECL Series cells?
The ECL Series includes electrochemical cell and probe options for the HPR-40 DEMS, including ECL-Static, ECL-Insight and ECL-Probe. These options support different experimental requirements, including coated working surfaces, direct electrode-to-MS connection and direct dissolved gas analysis.
Why is real-time gas analysis important in electrochemistry?
Real-time gas analysis helps researchers monitor gaseous and volatile species as electrochemical reactions occur. This supports investigation of reaction pathways, product selectivity, intermediates and changes linked to applied potential.
Explore DEMS and OEMS Solutions from Hiden Analytical
For laboratories working in electrochemistry, battery development, fuel cell research, electrocatalysis and real-time gas analysis, DEMS and OEMS provide valuable tools for connecting electrochemical performance with chemical product detection.
Learn more about Hiden Analytical’s dedicated DEMS and OEMS systems:
- HPR-40 DEMS for in situ, real-time electrochemical gas analysis
- HPR-20 OEMS for continuous online electrochemical mass spectrometry
To discuss application-specific requirements, cell compatibility, software integration or sampling interfaces, contact the Hiden Analytical team for support with DEMS and OEMS workflows.
