Improved Uranium Isotope Ratio Analysis in Liquid Sampling–Atmospheric Pressure Glow Discharge/Orbitrap FTMS Coupling through the Use of an External Data Acquisition System

Abstract

Isotope ratio (IR) analysis of natural abundance uranium presents a formidable challenge for mass spectrometry (MS): the required spectral dynamic range needs to enable the quantitatively accurate measurement of the 234UO2 species present at ∼0.0053% isotopic abundance. We address this by empowering a benchtop Orbitrap Fourier transform mass spectrometer (FTMS) coupled with the liquid sampling–atmospheric pressure glow discharge (LS-APGD) ion source and an external high-performance data acquisition system, FTMS Booster X2. The LS-APGD microplasma has demonstrated impressive capabilities regarding elemental and IR analysis when coupled with Orbitrap FTMS. Despite successes, there are limitations regarding the dynamic range and mass resolution that stem from space charge effects and data acquisition and processing restrictions. To overcome these limitations, the FTMS Booster was externally interfaced to an LS-APGD Q Exactive Focus Orbitrap FTMS to obtain time-domain signals (transients) and to process unreduced data. The unreduced time-domain data acquisition with user-controlled processing permit the evaluation of the effects of in-hardware transient phasing, increased transient lengths, advanced transient coadding, varying the length of a transient to be processed with a user-defined time increment, and the use of absorption-mode FT (aFT) processing methods on IR analysis. The added capabilities extend the spectral dynamic range of the instrument to at least 4–5 orders of magnitude and provide a resolution improvement from ∼70k to 900k m/Δm at 200 m/z. The empowered LS-APGD Orbitrap platform allows for the simultaneous measurement of 234UO2 and the prominent 235UO2 and 238UO2 isotopic species at their natural abundances, ultimately yielding improvements in performance when compared to previous uranium IR results on this same Q Exactive Focus instrument.

Drug-to-Antibody Ratio Estimation via Proteoform Peak Integration in the Analysis of Antibody–Oligonucleotide Conjugates with Orbitrap Fourier Transform Mass Spectrometry

“…Previously, similar external DAQ systems were interfaced with Q Exactive Orbitrap FTMS instruments for small molecule analyses. 45,46 The lengths of the transients acquired with the external and the in-built DAQ systems were comparable. FTMS Data Processing and Analysis.…”

“…However, owing to the recent advances in data acquisition electronics and allied digital signal processing, the time-domain data can be obtained from the contemporary FTMS instruments using the external high-performance DAQ systems and provided for data processing. 45,46,50 In practice, the optimum resolution (transient duration) for the analysis of a particular ADC/AOC sample may be unknown a priori. It was the case in the current work, where the limited sample amount (<100 μg) and expectedly high sample complexity suggested using a (relatively) highresolution setting on an Orbitrap FTMS (60,000 at m/z 200, which requires 128 ms transients) (Figure 1).…”

“…The manufacturers typically restrict both options. However, owing to the recent advances in data acquisition electronics and allied digital signal processing, the time-domain data can be obtained from the contemporary FTMS instruments using the external high-performance DAQ systems and provided for data processing. ,, …”

“…In parallel, it was coupled to an external high-performance DAQ system (FTMS Booster X2, Spectroswiss, Lausanne, Switzerland). Previously, similar external DAQ systems were interfaced with Q Exactive Orbitrap FTMS instruments for small molecule analyses. , The lengths of the transients acquired with the external and the in-built DAQ systems were comparable.…”

Vacuum Laser Photoionization inside the C-trap of an Orbitrap Mass Spectrometer: Resonance-Enhanced Multiphoton Ionization High-Resolution Mass Spectrometry

“…The aim of this technical development was the construction of a compact laser vacuum photoionization high-performance mass spectrometer and its combination with the analysis of aromatic compounds using a selective and sensitive REMPI ionization approach. In addition to the proof-of-the-concept demonstration, the analysis of polycyclic aromatic hydrocarbons (PAHs) by themselves is important for environmental health and toxicological research, requiring trace detection of the aromatic profile in complex samples. , Thus, reliable and confident PAH detection with high sensitivity and selectivity is of great analytical interest. − In contrast to the established ToF MS solutions, FTMS can deliver mass resolving power above 100 000 at m / z 200 and sub-ppm mass accuracy with 4–5 orders of spectral dynamic range . Based on standard mixtures, we show the capabilities and figures of merit for the direct gas-phase detection of volatile compounds, as well as the detection of heavier species by the gas chromatographic (GC) coupling.…”