Positive and negative ion mode ESI-MS and MS/MS for studying drug–DNA complexes

Pouteria lucuma Ruiz and Pav., known as the ‘Gold of the Incas’ or ‘lucuma’, is a subtropical fruit belonging to the Sapotaceae family, with a very sweet flavor, used to prepare cakes, ice creams as well as in the baking and dairy industries. To date, the content of primary metabolites is known, but little information is reported about the composition in specialized metabolites. Moreover, no study is reported on skin which represent an important agricultural waste due to the high demand for lucuma. In order to have a preliminary metabolite profile of Pouteria lucuma, the extracts of pulp and skin have been analyzed by LC-ESI/LTQOrbitrap/MS/MS in negative ion mode. The careful analysis of the accurate masses, of the molecular formulas and of the ESI/MS spectra allowed to identify specialized metabolites belonging to phenolic, flavonoid and polar lipid classes. The LC-MS/MS analysis guided the isolation of compounds occurring in the pulp extract whose structures have been characterized by spectroscopic methods including 1D- and 2D-NMR experiments and ESI-MS analysis. Furthermore, the phenolic content of the extracts along with the antioxidant activity of extracts and isolated compounds was evaluated.

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Studies on structural elucidation of delphinium alkaloids by using LC-ESI-MS technique.

JOURNAL OF ADVANCES IN CHEMISTRY ◽

10.24297/jac.v11i3.868 ◽

2015 ◽

Vol 11 (3) ◽

pp. 3399-3411

Author(s):

Bilal Ahmad Dar ◽

Mushtaq Ahmad Qurishi ◽

Aijaz Hussain Kanth

Keyword(s):

Mass Spectrometry ◽

Liquid Chromatography ◽

Negative Ion ◽

Tentative Identification ◽

Esi Ms ◽

Short Run ◽

Positive Mode ◽

Fragmentation Patterns ◽

Negative Ion Mode ◽

Mode Response

A rapid,sensitive and specific liquid chromatography-electron spray-mass spectrometry (LC-ESI-MS) method to identify the different diester-diterpenoid and monoester type alkaloids from delphinium cashmerianum Collected from Sopi Kargil. Chromatographic separation were achieved on c-18 coloumn and peaks determined by mass spectrometry in positive and negative modes.The validated method led to tentative identification of eight alkaloids on the basis of their retention times and fragmentation patterns. Results showed that the positive mode response was much higher than the negative ion mode .chromatographic conditions were optimized to obtain high resolution and short run time.

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Dependence of matrix effect on ionization polarity during LC–ESI–MS analysis of derivatized amino acids in some natural samples

European Journal of Mass Spectrometry ◽

10.1177/1469066717711026 ◽

2017 ◽

Vol 23 (5) ◽

pp. 245-253 ◽

Cited By ~ 6

Author(s):

Maarja-Liisa Oldekop ◽

Riin Rebane ◽

Koit Herodes

Keyword(s):

Amino Acids ◽

Matrix Effect ◽

Negative Ion ◽

Herbal Extracts ◽

Esi Ms ◽

Ms Analysis ◽

The Matrix ◽

Negative Ion Mode ◽

Positive Ion ◽

Sample Dilution

Matrix effect, the influence of co-eluting components on the ionization efficiency of the analyte, affects the trueness and precision of the LC–ESI–MS analysis. Derivatization can reduce or eliminate matrix effect, for example, diethyl ethoxymethylenemalonate (DEEMM) derivatives have shown less matrix effect compared to other derivatives. Moreover, the use of negative ion mode can further reduce matrix effect. In order to investigate the combination of derivatization and different ionization modes, an LC–ESI–MS/MS method using alternating positive/negative ion mode was developed and validated. The analyses in positive and negative ion modes had comparable limit of quantitation values. The influence of ESI polarity on matrix effect was investigated during the analysis of 22 DEEMM-derivatized amino acids in herbal extracts and honeys. Sample dilution approach was used for the evaluation of the presence of matrix effect. Altogether, 4 honeys and 11 herbal extracts were analyzed, and the concentrations of 22 amino acids in the samples are presented. In the positive ion mode, matrix effect was observed for several amino acid derivatives and the matrix effect was stronger in honey samples compared to the herbal extracts. The negative ion mode was free from matrix effect, with only few exceptions in honeys (average relative standard deviation over all analytes and matrices was 8%; SD = 7%). The matrix effect was eliminated in the positive ion mode by sample dilution and agreement between concentrations from the two ion modes was achieved for most amino acids. In conclusion, it was shown that the combination of derivatization and negative ion mode can be a powerful tool for minimizing matrix effect in more complicated applications.

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Should We Think Positive or Negative About Dihydrobenzofuran Neolignans? an ESI-MS/MS Study

10.26434/chemrxiv.12287786.v1 ◽

2020 ◽

Author(s):

Herbert Dias ◽

Eduardo Crevelin ◽

Vinicius Palaretti ◽

Ricardo Vessecchi ◽

Antônio Eduardo Crotti

Keyword(s):

Structural Features ◽

Biologically Active ◽

Negative Ion ◽

Esi Ms ◽

Product Ions ◽

Sequential Mass Spectrometry ◽

Negative Ion Mode ◽

Gas Phase Fragmentation ◽

Protonated Molecules ◽

Positive Ion

This study elucidates the gas-phase fragmentation pathways of a series of biologically active benzofuran neolignans (BNs) and dihydrobenzofuran neolignans (DBNs) by means of electrospray ionization accurate-mass tandem and sequential mass spectrometry (ESI-MS/MS and ESI-MSn) and thermochemical data estimated by using Computational Chemistry and the B3LYP/6-31+G(d,p) model. In their deprotonated forms, these compounds produced more diagnostic product ions as compared to the corresponding protonated molecules. Moreover, a series of odd-electron product ions (radical anions) were detected, which has not been reported for protonated DBNs. Direct C2H3O2• elimination from the precursor ion (deprotonated molecule) only occurred for the BNs and can help to distinguish these compounds from the DBNs. Although the product ion [M‒CH3OH]‒ emerged in the spectrum of all the DBNs analyzed here, the mechanism through which this ion originates strongly depends on specific structural features, so that further [M‒CH3OH]‒ fragmentation generates important diagnostic product ions. Comparison between the ESI-MS/MS data of these compounds in the negative ion mode (deprotonated molecule) and in the positive ion mode (protonated molecule) revealed that the negative ion mode provides much more information (at least one diagnostic product ion emerged for all the analyzed compounds) and does not require the use of additives to produce the precursor ions (deprotonated molecules).

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Should We Think Positive or Negative About Dihydrobenzofuran Neolignans? an ESI-MS/MS Study

10.26434/chemrxiv.12287786 ◽

2020 ◽

Author(s):

Herbert Dias ◽

Eduardo Crevelin ◽

Vinicius Palaretti ◽

Ricardo Vessecchi ◽

Antônio Eduardo Crotti

Keyword(s):

Structural Features ◽

Biologically Active ◽

Negative Ion ◽

Esi Ms ◽

Product Ions ◽

Sequential Mass Spectrometry ◽

Negative Ion Mode ◽

Gas Phase Fragmentation ◽

Protonated Molecules ◽

Positive Ion

This study elucidates the gas-phase fragmentation pathways of a series of biologically active benzofuran neolignans (BNs) and dihydrobenzofuran neolignans (DBNs) by means of electrospray ionization accurate-mass tandem and sequential mass spectrometry (ESI-MS/MS and ESI-MSn) and thermochemical data estimated by using Computational Chemistry and the B3LYP/6-31+G(d,p) model. In their deprotonated forms, these compounds produced more diagnostic product ions as compared to the corresponding protonated molecules. Moreover, a series of odd-electron product ions (radical anions) were detected, which has not been reported for protonated DBNs. Direct C2H3O2• elimination from the precursor ion (deprotonated molecule) only occurred for the BNs and can help to distinguish these compounds from the DBNs. Although the product ion [M‒CH3OH]‒ emerged in the spectrum of all the DBNs analyzed here, the mechanism through which this ion originates strongly depends on specific structural features, so that further [M‒CH3OH]‒ fragmentation generates important diagnostic product ions. Comparison between the ESI-MS/MS data of these compounds in the negative ion mode (deprotonated molecule) and in the positive ion mode (protonated molecule) revealed that the negative ion mode provides much more information (at least one diagnostic product ion emerged for all the analyzed compounds) and does not require the use of additives to produce the precursor ions (deprotonated molecules).

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A Mass Spectrometry-Based Approach for Characterization of Red, Blue, and Purple Natural Dyes

Molecules ◽

10.3390/molecules25143223 ◽

2020 ◽

Vol 25 (14) ◽

pp. 3223

Author(s):

Katarzyna Lech ◽

Emilia Fornal

Keyword(s):

High Performance ◽

Multiple Reaction Monitoring ◽

Natural Dyes ◽

Negative Ion ◽

Near Eastern ◽

Esi Ms ◽

Historical Objects ◽

Tandem Mass Spectrometric ◽

Negative Ion Mode ◽

Analytical Approaches

Effective analytical approaches for the identification of natural dyes in historical textiles are mainly based on high-performance liquid chromatography coupled with spectrophotometric detection and tandem mass spectrometric detection with electrospray ionization (HPLC-UV-Vis-ESI MS/MS). Due to the wide variety of dyes, the developed method should include an adequate number of reference color compounds, but not all of them are commercially available. Thus, the present study was focused on extending of the universal analytical HPLC-UV-Vis-ESI MS/MS approach to commercially unavailable markers of red, purple, and blue dyes. In the present study, HPLC-UV-Vis-ESI MS/MS was used to characterize the colorants in ten natural dyes (American cochineal, brazilwood, indigo, kermes, lac dye, logwood, madder, orchil, Polish cochineal, and sandalwood) and, hence, to extend the analytical method for the identification of natural dyes used in historical objects to new compounds. Dye markers were identified mostly on the basis of triple quadrupole MS/MS spectra. In consequence, the HPLC-UV-Vis-ESI MS/MS method with dynamic multiple reaction monitoring (dMRM) was extended to the next 49 commercially unavailable colorants (anthraquinones and flavonoids) in negative ion mode and to 11 (indigoids and orceins) in positive ion mode. These include protosappanin B, protosappanin E, erythrolaccin, deoxyerythrolaccin, nordamnacanthal, lucidin, santalin A, santalin B, santarubin A, and many others. Moreover, high-resolution QToF MS data led to the establishment of the complex fragmentation pathways of α-, β-, and γ- aminoorceins, hydroxyorceins, and aminoorceinimines extracted from wool dyed with Roccella tinctoria DC. The developed approach has been tested in the identification of natural dyes used in 223 red, purple, and blue fibers from 15th- to 17th-century silk textiles. These European and Near Eastern textiles have been used in vestments from the collections of twenty Krakow churches.

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Improved analysis of C26:0-lysophosphatidylcholine in dried-blood spots via negative ion mode HPLC-ESI-MS/MS for X-linked adrenoleukodystrophy newborn screening

Clinica Chimica Acta ◽

10.1016/j.cca.2012.03.026 ◽

2012 ◽

Vol 413 (15-16) ◽

pp. 1217-1221 ◽

Cited By ~ 24

Author(s):

Christopher A. Haynes ◽

Víctor R. De Jesús

Keyword(s):

Newborn Screening ◽

Dried Blood Spots ◽

Negative Ion ◽

Esi Ms ◽

Blood Spots ◽

Negative Ion Mode

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Unusual behavior of benzofuroxans under ESI MS conditions in negative ion mode

Mendeleev Communications ◽

10.1016/j.mencom.2014.04.014 ◽

2014 ◽

Vol 24 (3) ◽

pp. 165-166 ◽

Cited By ~ 6

Author(s):

Alexander O. Chizhov ◽

Nina N. Makhova ◽

Ilya V. Kuchurov ◽

Aleksei B. Sheremetev ◽

Sergei G. Zlotin

Keyword(s):

Negative Ion ◽

Unusual Behavior ◽

Esi Ms ◽

Negative Ion Mode

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Confounding contaminants in mass spectrometric reaction monitoring

10.26434/chemrxiv.7488737.v1 ◽

2018 ◽

Author(s):

Gilian T. Thomas ◽

Landon MacGillivray ◽

Natalie L. Dean ◽

Rhonda L. Stoddard ◽

Lars Yunker ◽

...

Keyword(s):

Mass Spectrometry ◽

Mass Spectrometric ◽

Negative Ion ◽

Reaction Monitoring ◽

Schlenk Flask ◽

Dynamic Analyses ◽

Rubber Septa ◽

Negative Ion Mode ◽

Mode A

Reactions carried out in the presence of rubber septa run the risk of additives being leached out by the solvent. Normally, such species are present at low enough levels that they do not interfere with the reaction significantly. However, when studying reactions using sensitive methods such as mass spectrometry, the appearance of even trace amounts of material can confuse dynamic analyses of reactions. A wide variety of additives are present in rubber along with the polymer: antioxidants, dyes, detergent, and vulcanization agents, and these are all especially problematic in negative ion mode. A redesigned Schlenk flask for pressurized sample infusion (PSI) is presented as a means of practically eliminating the presence of contaminants during reaction analyses.

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