Unravelling the factors that drive separation in differential mobility spectrometry: A case study of regioisomeric phosphatidylcholine adducts

Ieritano, Christian; Campbell, J. Larry; Hopkins, W. Scott

doi:10.1016/j.ijms.2019.116182

Cited by 6 publications

(8 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Silver ions interact with the π-moieties of alkene structures, which is utilized in silver chromatography to separate lipid species based on their degree of unsaturation [ 28 – 30 ]. The interaction between Ag + and π-moieties has also been utilized as an ionization reagent for mass spectrometric experiments, and to obtain information on the molecular structure [ 25 , 27 , 29 , 31 , 32 ]. Silver ions have been shown to increase the sensitivity of poorly ionizable species, [ 25 , 26 ] and to induce structural changes in the gas phase to allow for separation by ion mobility spectrometry (IMS) and tandem mass spectrometry [ 25 , 26 , 29 , 31 , 32 ].…”

Section: Introductionmentioning

confidence: 99%

“…The interaction between Ag + and π-moieties has also been utilized as an ionization reagent for mass spectrometric experiments, and to obtain information on the molecular structure [ 25 , 27 , 29 , 31 , 32 ]. Silver ions have been shown to increase the sensitivity of poorly ionizable species, [ 25 , 26 ] and to induce structural changes in the gas phase to allow for separation by ion mobility spectrometry (IMS) and tandem mass spectrometry [ 25 , 26 , 29 , 31 , 32 ]. The use of tandem mass spectrometry to discriminate lipid isomers is highly attractive due to its congruency with most modern MS systems capable of collision-induced dissociation (CID).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Quantitative determination of sn-positional phospholipid isomers in MSn using silver cationization

Lillja

Lanekoff

2022

Anal Bioanal Chem

View full text Add to dashboard Cite

Glycerophospholipids are one of the fundamental building blocks for life. The acyl chain connectivity to the glycerol backbone constitutes different sn-positional isomers, which have great diversity and importance for biological function. However, to fully realize their impact on function, analytical techniques that can identify and quantify sn-positional isomers in chemically complex biological samples are needed. Here, we utilize silver ion cationization in combination with tandem mass spectrometry (MSn) to identify sn-positional isomers of phosphatidylcholine (PC) species. In particular, a labile carbocation is generated through a neutral loss (NL) of AgH, the dissociation of which provides diagnostic product ions that correspond to acyl chains at the sn-1 or sn-2 position. The method is comparable to currently available methods, has a sensitivity in the nM–µM range, and is compatible with quantitative imaging using mass spectrometry in MS4. The results reveal a large difference in isomer concentrations and the ion images show that the sn-positional isomers PC 18:1_18:0 are homogeneously distributed, whereas PC 18:1_16:0 and PC 20:1_16:0 show distinct localizations to sub-hippocampal structures. Graphical abstract

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantitative determination of sn-positional phospholipid isomers in MSn using silver cationization

Lillja

Lanekoff

2022

Anal Bioanal Chem

View full text Add to dashboard Cite

show abstract

“…This dynamic process of peptide unfolding and re-folding yields a dynamic temperature-dependent ion CCS that, along with the effect of increased carrier gas viscosity at higher temperature (Mason and Mcdaniel, 1988; Hopkins, 2019), gives rise to differential mobility behavior. If one assumes that the ion quickly reaches thermal equilibrium, which is likely given the conditions of the DMS cell (1 atm of carrier gas), one can estimate the temperature-dependent ion CCS as a sum of the Boltzmann-weighted conformer CCSs (Ieritano et al, 2019a). This is plotted for [AAA + H] + in Figure 10.…”

Section: Application Of Bh Search Resultsmentioning

confidence: 99%

Augmenting Basin-Hopping With Techniques From Unsupervised Machine Learning: Applications in Spectroscopy and Ion Mobility

2019

Self Cite

View full text Add to dashboard Cite

Evolutionary algorithms such as the basin-hopping (BH) algorithm have proven to be useful for difficult non-linear optimization problems with multiple modalities and variables. Applications of these algorithms range from characterization of molecular states in statistical physics and molecular biology to geometric packing problems. A key feature of BH is the fact that one can generate a coarse-grained mapping of a potential energy surface (PES) in terms of local minima. These results can then be utilized to gain insights into molecular dynamics and thermodynamic properties. Here we describe how one can employ concepts from unsupervised machine learning to augment BH PES searches to more efficiently identify local minima and the transition states connecting them. Specifically, we introduce the concepts of similarity indices, hierarchical clustering, and multidimensional scaling to the BH methodology. These same machine learning techniques can be used as tools for interpreting and rationalizing experimental results from spectroscopic and ion mobility investigations (e.g., spectral assignment, dynamic collision cross sections). We exemplify this in two case studies: (1) assigning the infrared multiple photon dissociation spectrum of the protonated serine dimer and (2) determining the temperature-dependent collision cross-section of protonated alanine tripeptide.

show abstract

“…Ultimately, the determination of CCSs from DMS experiments relies on gauging the dynamic effective temperature of the ion in question during the SV duty cycle. This temperature range must then be correlated to the temperature-dependent evolution of ion structure to create a picture of the dynamic CCS of the ion. , As progress is made in this regard, the direct correlation of DMS measurements to molecular structure may become possible.…”

Section: Discussionmentioning

confidence: 99%

“…This temperature range must then be correlated to the temperature-dependent evolution of ion structure to create a picture of the dynamic CCS of the ion. 70,71 As progress is made in this regard, the direct correlation of DMS measurements to molecular structure may become possible.…”

Section: ■ Conclusionmentioning

confidence: 99%

How Hot Are Your Ions in Differential Mobility Spectrometry?

Ieritano

Featherstone

Haack

et al. 2020

J. Am. Soc. Mass Spectrom.

Self Cite

View full text Add to dashboard Cite

Ions can experience significant field-induced heating in a differential mobility cell. To investigate this phenomenon, the fragmentation of several para-substituted benzylpyridinium “thermometer” ions (R = OMe, Me, F, Cl, H, CN) was monitored in a commercial differential mobility spectrometer (DMS). The internal energy of each benzylpyridinium derivative was characterized by monitoring the degree of fragmentation to obtain an effective temperature, T eff, which corresponds to a temperature consistent with treating the observed fragmentation ratio using a unimolecular dissociation rate weighted by a Boltzmann distribution at a temperature T. It was found that ions are sufficiently thermalized after initial activation from the ESI process to the temperature of the bath gas, T bath. Once a critical field strength was surpassed, significant fragmentation of the benzylpyridinium ions was detected. At the maximum bath gas temperature (450 K) and separation voltage (SV; 4400 V) for our instrument, T eff for the benzylpyridinium derivatives ranged from 664 ± 9 K (p-OMe) to 759 ± 17 K (p-H). The extent of activation at a given SV depends on the ion’s mass, degrees of freedom, (N DoF), and collision frequency as represented by the ion’s collision cross section. Plots of T eff vs the product of ion mass and N DoF and the inverse of collision cross section produce strong linear relationships. This provides an attractive avenue to estimate ion temperatures at a given SV using only intrinsic properties. Moreover, experimentally determined T eff correlate with theoretically predicted T eff using with a self-consistent method based on two-temperature theory. The various instrumental and external parameters that influence T eff are additionally discussed.

show abstract

Unravelling the factors that drive separation in differential mobility spectrometry: A case study of regioisomeric phosphatidylcholine adducts

Cited by 6 publications

References 53 publications

Quantitative determination of sn-positional phospholipid isomers in MSn using silver cationization

Quantitative determination of sn-positional phospholipid isomers in MSn using silver cationization

Augmenting Basin-Hopping With Techniques From Unsupervised Machine Learning: Applications in Spectroscopy and Ion Mobility

How Hot Are Your Ions in Differential Mobility Spectrometry?

Contact Info

Product

Resources

About