JEOL USA Blog

In this post, I’m going to explain how DART-MS and ambient ionization can simplify and speed up chemical analysis by mass spectrometry. 

Mass spectrometry is one of the most sensitive and versatile methods for chemical analysis. For almost a century, if you wanted to analyze chemicals by mass spectrometry, you could only analyze samples that could be introduced into a vacuum chamber and evaporated by heating. The development of atmospheric pressure ion sources like atmospheric pressure chemical ionization and electrospray ionization in the 1970’s and 1980’s greatly expanded the range of samples that could be analyzed by MS. However, samples still had to be injected into a sealed ion source. The introduction of ambient ionization with DART-MS (Direct Analysis in Real Time mass spectrometry) and DESI (desorption electrospray ionization) in the early 2000’s made it possible to analyze samples in open air, with little or no sample preparation.

We developed DART at JEOL USA in late 2002 and early 2003, and JEOL introduced the AccuTOF-DART mass spectrometer at PittCon in 2005, winning the Pittcon Editors’ Gold Award for Best New Product.  

Very briefly, DART-MS uses a high voltage needle to create a glow discharge plasma in a gas such as helium, argon, or nitrogen. The gas flowing out of the glow discharge chamber (“flowing afterglow”) contains highly energetic excited-state atoms or molecules. Long-lived excited-state atoms (“metastable atoms”) produce charged particles (“ions”) that can be introduced into a vacuum system and analyzed by mass spectrometry. Typically, the DART-MS source reacts with water or oxygen in air. These atmospheric ions react with the sample to produce the ions that are detected by the mass spectrometer. The detailed reactions will be described in subsequent posts.

The DART gas is often heated to evaporate chemicals that have low volatility. In thermal desorption DART (TD DART-MS), the sample is heated directly and the vapors are introduced into the DART-MS gas stream. Because DART-MS analysis can be carried out in open air, the chemist can quickly analyze objects held in front of the mass spectrometer. This has led to widespread use of the JEOL AccuTOF-DART system in fields such as forensics, materials analysis, chemical synthesis, and plant biochemistry.

Analyzing a smokeless gunpowder particle.

JEOL USA congratulates University of Tokyo Professor Yuichi Ikuhara and Professor Naoya Shibata, recently awarded the Japan Academy Prize for development of State-of-the-Art Electron Microscopy and their contribution to Nano Interface Technology (Joint Research). As corroborators with JEOL, their work in developing the Magnetic-field-free Atomic-Resolution STEM (MARS), Annular Bright Field (ABF), and Optimum Bright Field STEM detector (OBF) is invaluable.

Ikuhara and Shibata have worked together to pioneer the cutting edge of scanning transmission electron microscopy (STEM) and to solve various problems in nanomaterials science, including:

Based on these series of research results, Ikuhara and Shibata are constructing the theory of nano-interface engineering leading to the design and creation of new materials focusing on the functions of interfaces and lattice defects.

Prof. Wil Bigelow with a detailed balloon model of the 2100F TEM column on his 100th birthday.

Friends of Prof. Wilbur (Wil) Bigelow, Professor Emeritus at University of Michigan and Fellow of the Microscopy Society of America, threw a surprise 100th birthday party for him at the University of Michigan’s Dept. of Materials Science & Engineering in Ann Arbor on March 16. (His actual birthday was March 18). Among his colleagues and past students that attended were renowned researchers Larry Allard and John Mardinly.

Larry Allard (Oak Ridge National Laboratory) reported that, “The department hired a local balloon artist to make the balloon model of the 2100F microscope, shown in the poster with a slightly younger Wil sitting in front. The picture was also placed in the cake. It was a total surprise to Wil. The balloon model took an entire day to construct...it was pretty unique. I did a presentation of some of his early history, including my training on the JEM-6A in 1963, through the early 70s, right after I returned to Ann Arbor after 2 years in Oak Ridge, when John Mardinly came into the lab, shortly after the 1st JSM-U3 SEM was acquired. John covered the next decade or so, which included acquisition of the 2nd JSM-U3 and the JEM-100CX AEM, and the naming of the EMAL (Electron Microprobe Analysis Laboratory). John Mansfield wrapped up with the final history of the EMAL, and the move of the lab from Main Campus to North Campus.” 

Prof. Wil Bigelow honored with a special cake and the blue and gold theme of University of Michigan.

It's an honor to know these great researchers and we wish Wil all the best in his 100th year!

The drive is on to improve the performance of Lithium-ion batteries, particularly to increase energy density, life cycle, and safety. However, during development and assessment of their performance, lithium-ion batteries can present unique challenges for characterization and analysis using electron microscopy.

The basic structure of Lithium-ion batteries (LIB) contains as many as 10 different thin films and at least that many solid−solid interfaces. These interfaces consist of thin layers of cathode material, insulating barriers, anode materials, metal current collectors, and the electrolyte. These various components are in the form of powders, sheets, and fluids and require assessment before and after assembly and after repeated charge/discharge operations. Researchers who are correlating electrochemical behavior to what is physically happening within the cell need to study the 3D microstructure of the battery components as well as the interfaces formed between those layers.

The efficiency of batteries and fuel cells is governed by the diffusion of ions, the transport of electrons and the chemical interactions of electrode/electrolyte materials. Engineers can routinely characterize the structure and properties of components that shed light on their behavior during electrochemical processes, including ion relocation, lattice expansion or contraction, phase transition and surface reconstruction.

Petroleum accounts for a large percentage of the world's energy consumption and is an extraordinarily complex material composed of many types of hydrocarbons with a wide variety of properties, making them difficult to analyze.

Different types of hydrocarbons present different challenges to analysis: Aromatic hydrocarbons strongly absorb UV light, which is ideal for Photoionization (PI); saturated hydrocarbons can be analyzed by using traditional Electron Ionization (EI), but this technique can lead to complex fragmentation that does not occur in PI and Field Ionization (FI) experiments; and crude oil is a complex material that contains high boiling point compounds, thus making it difficult to analyze by GC-MS but making it ideal for direct probe analysis using Field Desorption (FD).

Comprehensive two-dimensional gas chromatography-high resolution time-of-flight mass spectrometry (GCxGC-HRTOFMS) with EI is a powerful method for characterizing complex mixtures such as base oils. However, EI data can often lack a strong molecular ion signal for many hydrocarbons, thus making them difficult to identify.

Field Ionization (FI) and Field Desorption (FD), however, are soft ionization techniques that are well suited for hydrocarbons analysis because they generate molecular ions for most compounds, including saturated hydrocarbons, with minimal fragmentation. The resulting mass spectra are dominated by molecular ions, whether from the GC output (FI) or from the emitter surface (FD).

In Dr. John Dane’s research on The Analysis of Petroleum Samples Measured by Using GCxGC-HRTOFMS, a high-resolution time-of-flight mass spectrometer (HRTOFMS) equipped with an electron ionization/field ionization/field desorption (EI/FI/FD) combination ion source and a GCxGC thermal modulator system was used to analyze petroleum samples. Additionally, the GC-MS interface was modified to increase the temperature in this region, so that higher boiling point compounds could be analyzed by the GCxGC-HRTOFMS system.

Lithium-ion batteries (LIBs) are used to power portable electronics, electric vehicles, and grid storage solutions; they play a crucial role in driving sustainability and are an essential energy storage device. With the demand for electric vehicles and renewable energy sources continuing to rise, there is an increasing need to improve electrochemical storage. The search for new battery materials, alongside the drive to improve performance, and lower the cost of existing and new batteries, comes with its challenges.

Lithium has one of the highest electrochemical potentials compared to other metals, making it very active. Therefore, it releases the electron from the outer shell much faster than other metals, which makes it a good choice for battery research. 6/7Li are called ‘spin spies’ because they detect changes in structure, state of deterioration, Li-ion mobility, and quantitation during charging and discharging of the battery and have guided the synthesis of new anode, cathode and electrolyte materials.

A primary concern in finding new forms of electrolytes in secondary batteries is safety because electrolytes can leak in a battery and are very sensitive to temperature change, especially high temperatures.

With the recent high-profile introduction of ChatGPT and Bard it’s no secret that artificial intelligence is here to stay. No matter how far this technology progresses, however, the most important software for any instrumentation will always be the scientist running the experiment. Looking to the future, AI will super-charge scientific analysis with high-speed identification of unknown compounds, and that future might be closer than we think.

At JEOL, Dr. Masaaki Ubukata’s recent work on Automated Structural Analysis for Real Unknown Compounds combines artificial intelligence (AI) with GC-HRTOFMS to rapidly provide analysis results of known mass spectra, automatically perform qualitative analysis of unknown chemical compounds, and provide high quality structural analysis results.

Prior to the development of our new software, structural analysis of real unknown compounds required significant knowledge, experience, and time: sorting through structural information for EI fragment ions, identifying higher-mass m/z ions as functional groups and substructures, looking at low-mass m/z fragment ions to classify compounds, and working through possible McLafferty rearrangement to derive structures from the fragmentation.

In this AI-assisted workflow, deconvolution of GC-MS data into mass spectrum, library search, molecular ion search, accurate mass analysis, isotope pattern matching, and structural analysis can all happen within minutes.

This newly developed automated structural analysis software, msFineAnalysis AI, two different AI programs: First, to predict chemical formulas from EI and SI (soft ionization) data and, second, to assign candidate structure matches by using our newly developed database for structure analysis.

Typically, despite being the most popular method used in gas chromatography-mass spectrometry (GC-MS), electron ionization (EI) results in weak or absent molecular ions in the mass spectral data, making it difficult to identify unknowns by EI alone. However, this technology leverages soft ionization data for molecular ion information with the large number of fragment ions observed in EI mass spectra to automatically interpret this data into potential structural formulas, even if the operator has no knowledge of mass spectrometry or AI.

Because of this, the predicted structural formula of a detected component is automatically obtained, with the ability to analyze the structures of up to 50 unknown compounds in 3 minutes or less. With less time required to perform qualitative analysis for a variety of sample types containing complex mixtures of structurally-similar compounds, scientists have more free time for running additional samples or getting started on their next experiment.

For more than 30 years, the JEOL sales and service office in Mexico has been the resource for electron microscopes and microprobes, as well as NMR and Mass Spectrometers. We are proud to say that we partner with many well-known universities and organizations who are leading the way in research, and we are the preferred supplier for domestic industry.

JEOL de México continues our long history of dedication to providing support to our customers in education, research, and industry and encourage you to contact us at any time with your sales inquiries and service needs.

We are pleased to introduce our new Sales Manager, Erick Leyva. Erick is your primary contact for all sales enquiries regarding JEOL SEM, TEM, EPMA, Mass Spectrometers, and NMR Spectrometers, and manages our sales support organization. He has been with for JEOL for 4 years, and was promoted to Sales Manager of JEOL de México in 2022. He holds a Bachelor’s degree in Chemical Engineering from Universidad Nacional Autónoma de México (UNAM) with additional certificates from Harvard University and University of Michigan. He has also worked in sales at Anton Paar.

Alejandro Contreras is your primary contact for all service questions and requests for all JEOL instruments. Alejandro manages a department of 10 service engineers with expertise in JEOL instrumentation.

At JEOL de México we will continue to give the best support we can in our territory in sales, service and applications. By contacting Erick and Alejandro, JEOL de México customers can be confident they will have the best and fastest response time to their sales and service enquiries.