Atmospheric Pressure Ionization Mass Spectrometry

Tarr, Matthew A.; Zhu, Jie; Cole, Richard B.

doi:10.1002/9780470027318.a6003

Cited by 3 publications

(5 citation statements)

References 164 publications

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“…x z 2 protonated monomer analyte 2 2 proton bound dimer 2 neutral (2) While proton bound trimers can form at subambient temperatures and are observed in mobility spectra, ion lifetimes are submillisecond at or above 25 °C and are not commonly seen in applications of IMS today with 1 to 10 ms time scale. 29,30 Only reactions with hydrated protons are considered in models developed here although recent studies have demonstrated that precursor ions including O 2 + can be utilized at high electric fields and reduced pressures.…”

Section: Mh (H O) M M H (H O) Wh Omentioning

confidence: 99%

“…Analytical response in atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) − and ion mobility spectrometry (IMS) at ambient pressure , is governed by gas phase reactions between analyte neutrals and reagent ions, often derived from proton clusters in positive polarity. Such reactions occur in a significant number of ion sources for MS , including corona discharges, , electrospray ionization, − dielectric barrier discharges, , and soft X-rays. − One stable and reliable source at ambient pressure, the beta emitter 63 Ni, was used in early API MS instruments and can be found in IMS drift tubes in use today. , The foundations for understanding gas phase ion–molecule reactions were developed and refined by the mid-1970s with a broad experimental record for mass spectrometry including chemical ionization MS − and studies with ionization detectors. − These reactions as shown in eq for reactions between hydrated protons (reagent) and substances M (analyte) commonly occur at elevated or ambient pressure with ions at thermal energies.…”

Section: Introductionmentioning

confidence: 99%

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Parametric Sensitivity in a Generalized Model for Atmospheric Pressure Chemical Ionization Reactions

Lattouf

Anttalainen

Kotiaho

et al. 2021

J. Am. Soc. Mass Spectrom.

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Gas phase reactions between hydrated protons H+(H2O) n and a substance M, as seen in atmospheric pressure chemical ionization (APCI) with mass spectrometry (MS) and ion mobility spectrometry (IMS), were modeled computationally using initial amounts of [M] and [H+(H2O) n ], rate constants k 1 to form protonated monomer (MH+(H2O) x ) and k 2 to form proton bound dimer (M2H+(H2O) z ), and diffusion constants. At 1 × 1010 cm–3 (0.4 ppb) for [H+(H2O) n ] and vapor concentrations for M from 10 ppb to 10 ppm, a maximum signal was reached at 4.5 μs to 4.6 ms for MH+(H2O) x and 7.8 μs to 46 ms for M2H+(H2O) z . Maximum yield for protonated monomer for a reaction time of 1 ms was ∼40% for k 1 from 10–11 to 10–8 cm3·s–1, for k 2/k 1 = 0.8, and specific values of [M]. This model demonstrates that ion distributions could be shifted from [M2H+(H2O) z ] to [MH+(H2O) x ] using excessive levels of [H+(H2O) n ], even for [M] > 10 ppb, as commonly found in APCI MS and IMS measurements. Ion losses by collisions on surfaces were insignificant with losses of <0.5% for protonated monomer and <0.1% for proton bound dimer of dimethyl methylphosphonate (DMMP) at 5 ms. In this model, ion production in an APCI environment is treated over ranges of parameters important in mass spectrometric measurements. The models establish a foundation for detailed computations on response with mixtures of neutral substances.

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Section: Mh (H O) M M H (H O) Wh Omentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Parametric Sensitivity in a Generalized Model for Atmospheric Pressure Chemical Ionization Reactions

Lattouf

Anttalainen

Kotiaho

et al. 2021

J. Am. Soc. Mass Spectrom.

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“…In the positive-ion mode, proton transfer occurs from the adducts to the analyte. In the negative-ion mode, proton subtraction produces the molecular ion …”

Section: Introductionmentioning

confidence: 99%

“…In the negative-ion mode, proton subtraction produces the molecular ion. 12 The advantage of using APCI is that ionization occurs in the gaseous state than in the liquid state in ESI, which enables APCI to work with non-polar solvents. Also, APCI is less susceptible to matrix effects (including ion suppression) compared to ESI, and therefore, APCI can be considered for a wide range of applications including non-polar analytes.…”

Section: ■ Introductionmentioning

confidence: 99%

Effect of Position 1 Substituent and Configuration on APCI–MS Fragmentation of Norditerpenoid Alkaloids Including 1-epi-Condelphine

2022

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Norditerpenoid alkaloids (NDA) are hexacyclic highly oxygenated compounds, and the analysis of their 3D configuration is important as it helps to interpret their bioactive conformations. High-performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (LC/MS–APCI) is a promising technique to investigate NDA stereochemistry. The effect of the alpha (α)-substituent at carbon 1 and its configuration on the stability of NDA in the mass spectrometer was studied. It was observed that 1-OH NDA are more stable compared to 1-OMe NDA due to the intramolecular H-bonding that exists in 1-OH NDA. In addition, 1-epi-condelphine 9 was found to be less stable in the mass spectrometer compared to condelphine 7 as the nitrogen is no longer hydrogen-bonded to the β-hydroxyl at position 1, which highlights the importance of the substituent configuration at carbon 1.

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“…This produces spectra that generally contain just molecular ions with very little fragmentation, thus simplifying interpretation of datasets. 1 The technology has been applied across a wide range of disciplines and has enabled advances in areas such as drug metabolism, 2 proteomics, 3 metabolomics, 4,5 lipidomics, 6 and imaging. 7 The increasing ease of use and robustness of these once complex systems, combined with the provision of myriad software tools to confidently extract information from data, have moved this instrumentation into the hands of the bench scientist.…”

Section: Introductionmentioning

confidence: 99%

Novel Acoustic Loading of a Mass Spectrometer: Toward Next-Generation High-Throughput MS Screening

Sinclair

Stearns²,

Pringle

et al. 2016

SLAS Technology

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High-throughput, direct measurement of substrate-to-product conversion by label-free detection, without the need for engineered substrates or secondary assays, could be considered the "holy grail" of drug discovery screening. Mass spectrometry (MS) has the potential to be part of this ultimate screening solution, but is constrained by the limitations of existing MS sample introduction modes that cannot meet the throughput requirements of high-throughput screening (HTS). Here we report data from a prototype system (Echo-MS) that uses acoustic droplet ejection (ADE) to transfer femtoliter-scale droplets in a rapid, precise, and accurate fashion directly into the MS. The acoustic source can load samples into the MS from a microtiter plate at a rate of up to three samples per second. The resulting MS signal displays a very sharp attack profile and ions are detected within 50 ms of activation of the acoustic transducer. Additionally, we show that the system is capable of generating multiply charged ion species from simple peptides and large proteins. The combination of high speed and low sample volume has significant potential within not only drug discovery, but also other areas of the industry.

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Atmospheric Pressure Ionization Mass Spectrometry

Cited by 3 publications

References 164 publications

Parametric Sensitivity in a Generalized Model for Atmospheric Pressure Chemical Ionization Reactions

Parametric Sensitivity in a Generalized Model for Atmospheric Pressure Chemical Ionization Reactions

Effect of Position 1 Substituent and Configuration on APCI–MS Fragmentation of Norditerpenoid Alkaloids Including 1-epi-Condelphine

Novel Acoustic Loading of a Mass Spectrometer: Toward Next-Generation High-Throughput MS Screening

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