Antioxidant Pathways and One‐Electron Oxidation of Dopamine and Cysteine in Electrospray and On‐Line Electrochemistry Electrospray Ionization Mass Spectrometry

Mautjana, Nare Alpheus; Estes, Joshua; Eyler, John R.; Brajter-Toth, Anna

doi:10.1002/elan.200804279

Cited by 37 publications

(88 citation statements)

References 46 publications

(47 reference statements)

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“…7A) compared to the absence of DA ( Fig. 2A) in agreement with the effect of DA on CySH mass spectra reported previously [37]. Homocys-…”

Section: Esi Ms Of Gsh and Hcysh In The Presence Of Dopamine (Da)supporting

confidence: 92%

“…The CySH disulfide dimer, with relatively higher intensity [37] than observed here for GSSG and hCySSCyh, but lower than the DAQ/CySH adduct intensity, appears to increase (Table 1), along with the DAQ/CySH adduct, as EC cell voltage is increased. It is possible that the formation of CySSCy is kinetically competitive with DAQ/CySH formation as discussed previously [37], whereas the formation of GSSG and hCySSCyh is slow. In either case, the pathway proposed previously for the DAQ/CySH adduct formation [37] is supported by the experimental results.…”

Section: Ec/esi Ms Of Thiols In the Presence Of Dacontrasting

confidence: 56%

“…Similar to CySH/DAQ adduct [37], the adducts of (Fig. 7) increase in intensity with applied EC cell voltage (Fig.…”

Section: Ec/esi Ms Of Thiols In the Presence Of Damentioning

confidence: 87%

“…It is possible that the formation of CySSCy is kinetically competitive with DAQ/CySH formation as discussed previously [37], whereas the formation of GSSG and hCySSCyh is slow. In either case, the pathway proposed previously for the DAQ/CySH adduct formation [37] is supported by the experimental results.…”

Section: Ec/esi Ms Of Thiols In the Presence Of Damentioning

confidence: 95%

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Sensitivity of Positive Ion Mode Electrospray Ionization Mass Spectrometry in the Analysis of Thiol Metabolites

et al. 2009

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High signal intensities of glutathione (GSH), [GSHþ (m/z 136), are observed in ESI MS with on-line electrochemistry (EC). Dimers formed by H-bonding, which are not electrochemical products, are detected asþ (m/z 271) together with disulfide dimers GSSG, CySSCy and hCySSCyh,When dopamine is present a thiol/dopamine quinone (DAQ) adduct is observed. Formation of this adduct is proposed to occur by an electrochemical mechanism during ESI. Catalysis of thiol oxidation and analysis of thiol mixtures is addressed.

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“…7A) compared to the absence of DA ( Fig. 2A) in agreement with the effect of DA on CySH mass spectra reported previously [37]. Homocys-…”

Section: Esi Ms Of Gsh and Hcysh In The Presence Of Dopamine (Da)supporting

confidence: 92%

Section: Ec/esi Ms Of Thiols In the Presence Of Dacontrasting

confidence: 56%

“…Similar to CySH/DAQ adduct [37], the adducts of (Fig. 7) increase in intensity with applied EC cell voltage (Fig.…”

Section: Ec/esi Ms Of Thiols In the Presence Of Damentioning

confidence: 87%

Section: Ec/esi Ms Of Thiols In the Presence Of Damentioning

confidence: 95%

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Sensitivity of Positive Ion Mode Electrospray Ionization Mass Spectrometry in the Analysis of Thiol Metabolites

et al. 2009

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“…As a result of this inherent complexity in ESI, a distinct EC cell is desired to enable independent physical, electrical, and chemical control [32][33][34][35]. Two-electrode [34,[36][37][38][39][40][41] and three-electrode [33,35,[42][43][44] EC/ESI-MS configurations have been developed that achieve electrical decoupling through (a) floating the EC cell on the potential induced by the ESI high voltage or (b) electrically isolating the electronic circuits. An interesting example is an integrated three-electrode EC/ESI-MS device developed by Cole and coworkers [33,35,42] in which solution interacts with the EC working electrode a few millimeters before the end of the ESI source, leading to shorter response times (t r < 3 s; time between EC conversion and detection at three times the signal-to-noise (S/ N)) compared to typical configurations that have tubing connecting the EC cell and ESI emitter (t r is determined by tubing length, tubing internal diameter, and solution flow rate).…”

Section: Introductionmentioning

confidence: 99%

Paper-Based Electrochemical Cell Coupled to Mass Spectrometry

Liu

Perry

2015

J. Am. Soc. Mass Spectrom.

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Abstract. On-line coupling of electrochemistry (EC) to mass spectrometry (MS) is a powerful approach for identifying intermediates and products of EC reactions in situ. In addition, EC transformations have been used to increase ionization efficiency and derivatize analytes prior to MS, improving sensitivity and chemical specificity. Recently, there has been significant interest in developing paper-based electroanalytical devices as they offer convenience, low cost, versatility, and simplicity. This report describes the development of tubular and planar paper-based electrochemical cells (P-EC) coupled to sonic spray ionization (SSI) mass spectrometry (P-EC/SSI-MS). The EC cells are composed of paper sandwiched between two mesh stainless steel electrodes. Analytes and reagents can be added directly to the paper substrate along with electrolyte, or delivered via the SSI microdroplet spray. The EC cells are decoupled from the SSI source, allowing independent control of electrical and chemical parameters. We utilized P-EC/SSI-MS to characterize various EC reactions such as oxidations of cysteine, dopamine, polycyclic aromatic hydrocarbons, and diphenyl sulfide. Our results show that P-EC/SSI-MS has the ability to increase ionization efficiency, to perform online EC transformations, and to capture intermediates of EC reactions with a response time on the order of hundreds of milliseconds. The short response time allowed detection of a deprotonated diphenyl sulfide intermediate, which experimentally confirms a previously proposed mechanism for EC oxidation of diphenyl sulfide to pseudodimer sulfonium ion. This report introduces paper-based EC/MS via development of two device configurations (tubular and planar electrodes), as well as discusses the capabilities, performance, and limitations of the technique.

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Current Electrospray Mass Spectrometry: an Overview. Part A. Analyte Atomization

Verkerk

2015

Encyclopedia of Analytical Chemistry

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Electrospray ionization (ESI) is an atomization and ionization method through which a solution‐phase analyte can be transferred via minute charged droplets into the gas‐phase as an ion. The first part of this two‐part review on electrospray mass spectrometry considers the formation of these minute charged droplets. Atomization of liquids can take place through mechanical or electrostatic breakup of a liquid jet. In the absence of an electric field, charged droplets of both polarities are formed because of the disruption of the electrical double layer at the air–water interface. Addition of an electric field results in the formation of charged droplets of a single polarity. At sufficiently high electric field strength, mechanical jet disruption is replaced by electrostatic jet disruption giving the highest yield of charged droplets; this is the commonly used conductive DC electrospray. More recent means of forming charged droplets by DC or AC electric fields are discussed in the following sections. Mechanisms for reducing the droplet electrostatic stress such as droplet fragmentation are reviewed in the final section. These processes form the basis for the creation of charged gas‐phase analytes that is described in Current Electrospray Mass Spectrometry: an Overview. Part B. Analyte Charging.

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Antioxidant Pathways and One‐Electron Oxidation of Dopamine and Cysteine in Electrospray and On‐Line Electrochemistry Electrospray Ionization Mass Spectrometry

Cited by 37 publications

References 46 publications

Sensitivity of Positive Ion Mode Electrospray Ionization Mass Spectrometry in the Analysis of Thiol Metabolites

Sensitivity of Positive Ion Mode Electrospray Ionization Mass Spectrometry in the Analysis of Thiol Metabolites

Paper-Based Electrochemical Cell Coupled to Mass Spectrometry

Current Electrospray Mass Spectrometry: an Overview. Part A. Analyte Atomization

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