Electron Ionization Mass Spectrometry for Both Liquid and Gas Chromatography in One System without the Need for Hardware Adjustments

Tsizin, Svetlana; Fialkov, Alexander B.; Amirav, Aviv

doi:10.1021/jasms.0c00136

Cited by 13 publications

(10 citation statements)

References 50 publications

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“…We developed and employed electron ionization LC-MS with Cold EI 36 either with separation or in its flow-injection analysis mode. 37 It can serve for having better sensitivity than SIRTA due to its use of much higher solvent flow rate but it involves the addition of hardware and thus cost and complexity.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, flow injection with standard EI typically uses a low, sub-μL/min solvent flow rate (0.4 μL/min , ) and thus can experience relatively long void time. We developed and employed electron ionization LC-MS with Cold EI either with separation or in its flow-injection analysis mode . It can serve for having better sensitivity than SIRTA due to its use of much higher solvent flow rate but it involves the addition of hardware and thus cost and complexity.…”

Section: Discussionmentioning

confidence: 99%

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Sample Injection for Real-Time Analysis (SIRTA) Using GC-MS with Cold EI

Elkabets,

Neumark,

Amirav

2024

J. Am. Soc. Mass Spectrom.

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There is a continual demand for advanced methods and instruments for real-time analysis (RTA). Most of the current RTA techniques based on MS involve ambient desorption ionization technology. However, flow injection of liquid extracted samples is another option without added modifications or cost to existing LC-MS instruments. In this work, we introduce a new RTA approach named sample injection for real-time analysis (SIRTA) using GC-MS with Cold EI. In SIRTA, the standard GC column is replaced with a 1 m long 0.1 mm I.D. fused silica capillary that connects the GC injector to the MS transfer-line of Cold EI. Thus, SIRTA with Cold EI imposes no need for any additional instrumentation; hence, it is characterized by zero added cost. Like in flow injection in MS of LC-MS, the sample is dissolved in ∼1 mL methanol or another solvent. Subsequently, the vial is placed in the GC-MS autosampler while using a standard syringe for injection without any GC separation. The analysis takes merely 0.2−0.7 min, ensuring rapid and consecutive analyses. Unlike standard EI, Cold EI enables SIRTA by taking advantage of its fly through open ion source to avoid overwhelming the ion source during the elution of solvents while still providing enhanced molecular ions for nearly all analytes. In this study, we demonstrated SIRTA Cold EI analysis of 12 compounds and 7 mixtures, including various prescription and illicit drugs, cannabis and petroleum samples, and other synthetic organic compounds including those with molecular weight up to 800 g/mol.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Sample Injection for Real-Time Analysis (SIRTA) Using GC-MS with Cold EI

Elkabets,

Neumark,

Amirav

2024

J. Am. Soc. Mass Spectrom.

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“…Source: Reprinted with the permission of Ref. [93]. Copyright (2020), American Society for Mass Spectrometry developments, now EI-MS has the potential to allow the coexistence of GC and LC-and even supercritical fluid chromatography-in a single instrument.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, the Amirav Research Group introduced an instrument that combines GC-EI-MS and LC-EI-MS [93]. The system quickly switches between the two modes from the same software without any instrumental modification, even allowing GC-MS and LC-MS data acquisition in the same chromatogram and using conventional or Cold-EI.…”

Section: Ei-ms: Quo Vadis?mentioning

confidence: 99%

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Electron ionization mass spectrometry: Quo vadis?

et al. 2022

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Mass spectrometry (MS) is a fundamental technique to identify compounds by their mass-to-charge ratio. It is known that MS can only detect target compounds when they are converted to ions in the gas phase. The ionization procedure is considered one of the most critical steps, and there are distinct techniques for it. One of them is electron ionization (EI), a widely used hard-ionization technique capable of generating several ions due to the excess energy employed. The existence of distinct ionization mechanisms turns EI capable of producing a fingerprintlike spectrum for each molecule. So, it is an essential technique for obtaining structural information. EI is often combined with chromatography to obtain a practical introduction of pretreated samples despite its excellent performance. EI-MS has been applied coupled with gas chromatography (GC) since the 1960s as both are very compatible. Currently, analytes of interest are more suitable for liquid chromatography (LC) analysis, so there are researchers dedicated to developing suitable interfaces for coupling LC and EI-MS. EI excels, as a reliable technique to fill the gap between GC and LC, possibly allowing them to coexist in a single instrument. In this work, the authors will present the fundamentals of EI-MS, emphasizing the development over the years, coupling with gas and LC, and future trends.

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Analysis of impurities in pharmaceuticals by LC‐MS with cold electron ionization

2020

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Pharmaceuticals require careful and precise determination of their impurities that might harm the user upon consumption. Although today, the most common technique for impurities identification is liquid chromatography-mass spectrometry (LC-MS/MS), it has several downsides due to the nature of the ionization method. Also, the analyses in many cases are targeted thus despite being present, some of the compounds will not be revealed. In this paper, we propose and show a new method for untargeted analysis and identification of impurities in active pharmaceutical ingredients (APIs). The instrument used for these analyses is a novel electron ionization (EI) LC-MS with supersonic molecular beams (SMB). The EI-LC-MS-SMB was implemented for analyses of several drug samples spiked with an impurity. The instrument provides EI mass spectra with enhanced molecular ions, named Cold EI, which increases the identification probabilities when the compound is identified with the aid of an EI library like National Institute of Standards and Technology (NIST). We analyzed ibuprofen and its impurities, and both the API and the expected impurity were identified with names and structures by the NIST library. Moreover, other unexpected impurities were found and identified proving the ability of the EI-LC-MS-SMB system for truly untargeted analysis. The results show a broad dynamic range of four orders of magnitude at the same run with a signal-to-noise ratio of over 10 000 for the API and almost uniform response.

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Electron Ionization Mass Spectrometry for Both Liquid and Gas Chromatography in One System without the Need for Hardware Adjustments

Cited by 13 publications

References 50 publications

Sample Injection for Real-Time Analysis (SIRTA) Using GC-MS with Cold EI

Sample Injection for Real-Time Analysis (SIRTA) Using GC-MS with Cold EI

Electron ionization mass spectrometry: Quo vadis?

Analysis of impurities in pharmaceuticals by LC‐MS with cold electron ionization

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