Detection of transient dopamine antioxidant radicals using electrochemistry in electrospray ionization mass spectrometry

Iftikhar, Imran; El-Nour, Kholoud M. Abou; Brajter-Toth, Anna

doi:10.1016/j.electacta.2017.07.087

Cited by 29 publications

(41 citation statements)

References 41 publications

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“…L‐DOPA (L‐3,4‐dihydroxyphenylalanine) and adrenaline (epinephrine) were purchased from Tocris Bioscience, Bristol, and Sigma Aldrich (St. Louis, MO), respectively. Mobile phases used in ESI and EC/ESI MS were described previously and consisted of 50/49/1 volume % methanol/water/formic acid (pH∼3), glacial acetic acid (pH∼4) or ammonium acetate (pH∼6). Conductivity of the mobile phases was 1568, 121.8 and 59.9 mS/cm, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…APEX 4.7‐T FT‐ICR mass spectrometer (Bruker Daltonics, Billerica, MA) with a modified ESI interface has been described . The MS system used in this work is schematically illustrated in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

“…By adjusting EC cell voltage in the on‐line electrochemical cell in EC/MS, in addition to chemical characterization of the intermediates and products by MS during oxidations, new information about reactivity of reactants, intermediates and products could be accessed in real time, with ca. 3 ms time resolution ,,,. Additional chemical information could be obtained by interrogating the intermediates and products formed on‐line, in the gas phase in the MS system by spectroscopy .…”

Section: Introductionmentioning

confidence: 99%

“…Additional chemical information could be obtained by interrogating the intermediates and products formed on‐line, in the gas phase in the MS system by spectroscopy . Recently on‐line MS investigations of oxidations have been simplified by investigating the oxidations accompanying ESI, which is inherently an electrochemical process, which has extended the scope of the MS investigations of biologically relevant oxidations …”

Section: Introductionmentioning

confidence: 99%

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DOPA and Adrenaline Oxidation Kinetics and Intermediates Identified by Electrospray Ionization Mass Spectrometry in Real Time

2018

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DOPA and adrenaline (Adr) oxidation intermediates were identified using electrospray ionization mass spectrometry (ESI MS) by exploiting electrochemical oxidation reactions that occur during ESI. In addition, on‐line MS monitoring of the oxidations allowed evaluation of DOPA and Adr oxidation kinetics with approximately 3 ms time resolution. Kinetic information was confirmed by on‐line electrochemistry/ESI MS (EC/ESI MS). Application of an EC cell voltage in EC/ESI MS increased the oxidation rates and MS detection sensitivity of intermediates. During ESI and EC/ESI MS, oxidation rates were DOPADA , and cyclic leucochrome oxidation rates were DA>Adr>DOPA. Formation of radical semiquinones of Adr and DOPA through OH. radical‐initiated oxidation pathways was indicated, as reported for DA. Images of catecholamine oxidation pathways obtained with high time resolution, using MS, underscore the differences between the reactivity of DOPA, Adr, and DA.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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DOPA and Adrenaline Oxidation Kinetics and Intermediates Identified by Electrospray Ionization Mass Spectrometry in Real Time

2018

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“…5,6 The UA concentration in blood and urine is usually related to diseases such as Lesch-Nyhan syndrome, hyperuricemia, gout and kidney stones. 7,8 Therefore, the ability to detect and quantify these biological species is very important.…”

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confidence: 99%

Hollow, Spherical, Poly(3,4-ethylenedioxythiophene)-Bearing Methanethiol as a Gold Stabilizer for High-Efficiency Electrochemical Sensors

Ali¹,

Abdiryim²,

Huang³

et al. 2018

J. Electrochem. Soc.

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Conducting polymers decorated with noble metals are good electrochemical sensors for biological species. In this work, we developed a polymer of methanethiol-grafted poly(3,4-ethylenedioxythiophene) hollow spheres (Poly(EDOT-MeSH)) using SiO 2 nanospheres as a hard template. The Poly(EDOT-MeSH) spheres were used as both a reductant and stabilizer to decorate gold nanoparticles (Au NPs). FTIR, XRD, EDX, SEM and TEM analyses were used to characterize the Poly(EDOT-MeSH)/Au hollow spheres. The chemical bond between S and Au was confirmed by XPS. The electrochemical performance of the Poly(EDOT-MeSH)/Au hollow spheres was determined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The results revealed that the Poly(EDOT-MeSH)/Au hollow sphere-based electrochemical sensor possesses an excellent conductivity and high redox reversibility with detection limits (S/N = 3) of 5.3, 0.04 and 0.12 μM in the linear ranges of 50-320 μM, 0.05 μM − 780 μM and 0.8 μM − 250 μM for the determination of AA, DA and UA, respectively. These results will further the development of this type of electrochemical sensor for biological species. Small biological species usually coexist in physiological fluids, which are very important for maintaining the functions of organisms.1,2 As typical biological species, dopamine (DA), uric acid (UA) and ascorbic acid (AA) are important components of the neural system and play significant roles in physiological functions.3,4 DA is a natural neurotransmitter that plays an important role in controlling the central nervous system and coordinating normal cardiovascular, renal, and hormonal functions. 5,6 The UA concentration in blood and urine is usually related to diseases such as Lesch-Nyhan syndrome, hyperuricemia, gout and kidney stones. 7,8 Therefore, the ability to detect and quantify these biological species is very important. Several analytical techniques, such as liquid chromatography, 9 ultraviolet visible spectroscopy, 10 capillary electrophoresis, 11,12 chemiluminescence 13,14 and spectrometry 15 have been used to detect single or multiple biological species. However, most of these techniques require specialized, expensive instruments and can be utilized only for individual determination. In the last few years, electrochemical techniques have attracted attention for the determination of multiple components due to their simplicity, low cost, minimal analysis time, high sensitivity, good selectivity and simple instrumentation. [16][17][18] However, the electrochemical oxidation of DA and UA is difficult to observe with conventional electrodes, such as glassy carbon, gold and platinum electrodes, because the oxidation products cause electrode surface fouling. 3,19 In addition, AA co-exists with DA and UA in most biological fluids, and the AA concentration is higher than that of DA and UA (100-1000 times higher than that of DA). 20 The AA oxidation peak often overlaps with the DA and UA peaks because their oxidation potentials on conventional electrodes are nearly equal. 21,22 To...

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Accelerating Electrochemical Reactions in a Voltage‐Controlled Interfacial Microreactor

et al. 2020

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Microdroplet chemistry is attracting increasing attention for accelerated reactions at the solution-air interface. We report herein a voltage-controlled interfacial microreactor that enables acceleration of electrochemical reactions which are not observed in bulk or conventional electrochemical cells. The microreactor is formed at the interface of the Taylor cone in an electrospray emitter with a large orifice, thus allowing continuous contact of the electrode and the reactants at/near the interface. As a proof-of-concept, electrooxidative CÀH/NÀH coupling and electrooxidation of benzyl alcohol were shown to be accelerated by more than an order of magnitude as compared to the corresponding bulk reactions. The new electrochemical microreactor has unique features that allow i) voltage-controlled acceleration of electrochemical reactions by voltage-dependent formation of the interfacial microreactor; ii) "reversible" electrochemical derivatization; and iii) in situ mechanistic study and capture of key radical intermediates when coupled with mass spectrometry.

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Detection of transient dopamine antioxidant radicals using electrochemistry in electrospray ionization mass spectrometry

Cited by 29 publications

References 41 publications

DOPA and Adrenaline Oxidation Kinetics and Intermediates Identified by Electrospray Ionization Mass Spectrometry in Real Time

DOPA and Adrenaline Oxidation Kinetics and Intermediates Identified by Electrospray Ionization Mass Spectrometry in Real Time

Hollow, Spherical, Poly(3,4-ethylenedioxythiophene)-Bearing Methanethiol as a Gold Stabilizer for High-Efficiency Electrochemical Sensors

Accelerating Electrochemical Reactions in a Voltage‐Controlled Interfacial Microreactor

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