Methylene Blue-Mediated Electrocatalytic Detection of Hexavalent Chromium

Korshoj, Lee E.; Zaitouna, Anita; Lai, Rebecca Y.

doi:10.1021/acs.analchem.5b00197

Cited by 84 publications

(46 citation statements)

References 25 publications

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“…[10] Sensors based on nanomaterials were also reported. [11][12][13][14][15] Most of these sensors, however,s uffer from low selectivity and poor stability.…”

Section: Introductionmentioning

confidence: 99%

In Vitro Selection of Chromium‐Dependent DNAzymes for Sensing Chromium(III) and Chromium(VI)

Zhou

Vazin

et al. 2016

Chemistry A European J

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Chromium is a very important analyte for environmental monitoring, and developing biosensors for chromium is a long-standing analytical challenge. In this work, in vitro selection of RNAcleaving DNAzymes was carried out in the presence of Cr 3+ . The most active DNAzyme turned out to be the previously reported lanthanide-dependent Ce13d DNAzyme. While the Ce13d activity was ~150-fold lower with Cr 3+ compared to that with lanthanides, the activity of lanthanides and other competing metals was masked by using a phosphate buffer, leaving Cr 3+ the only metal that can activate Ce13d. With 100 µM Cr 3+ , the cleavage rate is 1.6 h -1 at pH 6.Using a molecular beacon design, Cr 3+ was measured with a detection limit of 70 nM, significantly lower than the U.S. Environmental Protection Agency (EPA) limit (11 μM). Cr(VI) was measured after its reduction by NaBH4 to Cr 3+ , and it can be sensed with a similar detection limit of 140 nM Cr(VI), lower than the EPA limit of 300 nM. This sensor was tested for chromium speciation analysis in a real sample, supporting its application for environmental monitoring. At the same time, it has enhanced our understanding on the interaction between chromium and DNA.3

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“…[10] Sensors based on nanomaterials were also reported. [11][12][13][14][15] Most of these sensors, however,s uffer from low selectivity and poor stability.…”

Section: Introductionmentioning

confidence: 99%

In Vitro Selection of Chromium‐Dependent DNAzymes for Sensing Chromium(III) and Chromium(VI)

Zhou

Vazin

et al. 2016

Chemistry A European J

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“…65,66 Final concentrations of species were: 3.1 mM CaSO4, 1.3 mM MgSO4, 38 μM K2SO4, 4 mM NaHCO3, 330 μM NaCl, 2.6 mM Na2SO4, and 3.75 μM NaBr. For probe 2 the fluoride concentration was adjusted to 2x of the indicated final fluoride concentration using NaF and the resulting solution was mixed with an equal volume of 10 mM HEPES (pH = 7.4).…”

Section: Selectivity and Competition Assaymentioning

confidence: 99%

The 8-Silyloxyquinoline Scaffold as a Versatile Platform for the Sensitive Detection of Aqueous Fluoride

Zhou

Lai

et al. 2015

Anal. Chem.

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Utilizing a novel 8-silyloxyquinoline scaffold, we demonstrate the ability to synthesize fluorogenic probes for the sensitive and selective detection of inorganic fluoride (NaF) in aqueous samples. Our initial probe design (2) is capable of detecting inorganic fluoride at levels as low as 3.8 μM (72 ppb) in aqueous solutions, well below PHS recommended levels for drinking water (0.7−1.2 ppm), placing this probe among the most sensitive fluoride sensors reported to date. Furthermore, our results highlight the utility of the readily modifiable 8silyloxyquinoline scaffold for the design of tailored fluoride sensing platforms. We demonstrate the ability to rationally tune the fluorescence and physical properties of the 8-silyloxyquinoline scaffold, producing a red-shifted fluoride probe (4) capable of detecting 50 μM (0.95 ppm) NaF in aqueous samples using a straightforward test-strip-based assay format. Taken together this work provides a template for the design of fluoride sensors capable of reporting on relevant concentrations of fluoride in the laboratory and in the field.

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“…However, some of the most sensitive and information‐rich voltammetric methods employ an alternating sinusoidal or square‐wave potential, which are currently not developed for BPEs. Several recent examples illustrate the enhanced signal afforded by ACV in the context of electrochemical sensing of clinical and environmental analytes . Such sensors meet many of the requirements for PON devices, in that they are reagent‐less, reusable, relatively fast, and sensitive .…”

Section: Introductionmentioning

confidence: 99%

“…Several recent examples illustrate the enhanced signal afforded by ACV in the context of electrochemical sensing of clinical and environmental analytes. [10][11][12][13][14][15][16][17] Such sensors meet many of the requirements for PON devices, in that they are reagent-less, reusable, relatively fast, and sensitive. [11] Therefore, ACV, in the context of BPEs, creates a promising platform for multiplexed PON sensors.…”

Section: Introductionmentioning

confidence: 99%

Alternating Current Voltammetry at a Bipolar Electrode with Smartphone Luminescence Imaging for Point‐of‐Need Sensing

2020

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Bipolar electrochemistry allows for facile arraying of tens to thousands of electrochemical sensors that can be controlled by a single pair of driving electrodes. While bipolar electrodes (BPEs) have been applied to many sensing motifs, their sensitivity and specificity are limited by the lack of diversity in voltammetric methods that have been developed for these wireless electrodes. In this study, electrochemiluminescence (ECL) from the co‐oxidation of Ru(bpy)32+ and tripropylamine (TPA) is evaluated as a reporting reaction for alternating current voltammetry (ACV) on a BPE at frequencies of 1.0 Hz and 5.0 Hz. We observe sinusoidal alternating luminescence that follows a similar trend to that of the simultaneously monitored current – a plot of the amplitude versus potential approximates a bell‐shaped curve. Notably, the luminescent response to the current is detected with a smartphone, which underscores the portability of this method. The fidelity of the transduced signal is determined both in a traditional 3‐electrode configuration and at a BPE. These experimental results indicate that the alternating luminescence follows the current sufficiently for quantitative sensing but is diminished at higher frequencies and peaks at a shifted potential. These results are significant because they demonstrate the potential for application of ACV at BPE arrays for multiplexed point‐of‐need sensors and provide guidance for the selection of reporting reactions in this context.

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Methylene Blue-Mediated Electrocatalytic Detection of Hexavalent Chromium

Cited by 84 publications

References 25 publications

In Vitro Selection of Chromium‐Dependent DNAzymes for Sensing Chromium(III) and Chromium(VI)

In Vitro Selection of Chromium‐Dependent DNAzymes for Sensing Chromium(III) and Chromium(VI)

The 8-Silyloxyquinoline Scaffold as a Versatile Platform for the Sensitive Detection of Aqueous Fluoride

Alternating Current Voltammetry at a Bipolar Electrode with Smartphone Luminescence Imaging for Point‐of‐Need Sensing

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