Voltammetric and microscopical investigation of the properties and behaviors of individual mercury micro-droplets

Liu, Cheng; Cheng, Wenxue; Zeng, Qiang; Huang, Xinjian; Wang, Lishi

doi:10.1016/j.jelechem.2016.11.052

Cited by 13 publications

(12 citation statements)

References 17 publications

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“…The latter causes the rise in the transmural capacitance C , which can be evaluated by the changes in charge when a nanoparticle translocation occurs. , As shown in Figure , a form of voltammogram can be recovered from the raw time domain current response in a sinusoidal voltage circle ,, (bias voltage ± excitation amplitude of −600.0 mV ± 300.0 mV). In particular, all nanoparticle translocations result in a significant increment in charge by referring to a larger hysteresis between the forward and reverse traces in the voltammograms. , In this way, the transmural capacitance increment due to the nanoparticle translocations can be determined according to eqs – to be 13.13 pF for Au nanoparticles, 5.152 pF for SiO 2 nanoparticles, and 6.421 pF for Ag nanoparticles.…”

Section: Resultsmentioning

confidence: 99%

“…Both resistive-pulse and phase angle measurements are conducted on a homemade potential instrument with a Faraday cage to minimize the external electromagnetic influences (Scheme S1). The compositions and functionalities of the homemade instrument was addressed previously in somewhere else, ,,− but in brief, the instrument is composed of the following three main parts: a compact ultralow current potentiostat, a data acquisition card (NI USB6521, National Instruments Co.), and a Windows-based controlling and data analyzing software written with C++ Builder. In particular, the potentiostat consists of a 16-bit waveform generator (M4x.6621-x4, Spectrum Co.), an oscilloscope (PXIe-5170), and three operational amplifiers (LMC6002) with the classic adder-type configuration.…”

Section: Methodsmentioning

confidence: 99%

“…However, under the excitation of a large-amplitude sine wave potential, the current signal is endowed with a periodic sinusoidal property, making its transient frequency feature be changed to the constant frequency feature as a consequence. The current signal in the time domain can thus be demonstrated as a fundamental harmonic in the frequency domain by STFT. − In our previous studies, the fundamental harmonic is illustrated at a certain phase angle, which is further dedicated as the unique “fingerprint” for the harmonic. , Interestingly, there would be a significant difference in fingerprint phase angles even though they originate from analytes with very similar properties . Therefore, the detection with improved selectivity can be achieved in the frequency domain by simply locking the specific fingerprint phase angles of analytes.…”

Section: Introductionmentioning

confidence: 99%

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A Fourier Transform-Induced Data Process for Label-Free Selective Nanopore Analysis under Sinusoidal Voltage Excitations

et al. 2020

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Nanopore analysis based on a resistive-pulse technique is an attractive tool for single-molecule detection in different fields, but it suffers a great drawback in selectivity. A common solution to this challenge is to add extra sensing aptamers and labels to analytes by improving the sensitivity of their pulses for distinguishing. Compared to the labeling methods, we alternatively develop and demonstrate a novel data process for label-free nanopore analysis that enables the conversion of resistive current signals to more specific frequency domain phase angle features with the contribution from both sinusoidal voltage excitation and Fourier transform. In particular, we find that the transmural capacitance induced by nanoparticle translocations under a sinusoidal voltage plays an important role in this process, making phase angle features more pronounced. In practical applications, the method is successfully applied to directly distinguish the translocation events through a nanopipette by their unique phase angles for similarly sized SiO2, Ag, and Au nanoparticles and soft living organisms of HeLa and LoVo and even in a more complicated case of a SiO2, Ag, and Au nanoparticle mixture.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Fourier Transform-Induced Data Process for Label-Free Selective Nanopore Analysis under Sinusoidal Voltage Excitations

et al. 2020

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“…Despite the comparative reduction in toxicity at mercury film electrodes, the presence of mercury microdroplets [11] open to the environment harbors the risk of outgassing, which may be harmful in larger amounts [8a,12] . While coalescence of mercury drops on electrode surfaces during growth has been reported, [13] the fate of mercury microdroplets after deposition has not received much attention. In some applications, the mercury film is formed in situ during electroanalysis to avoid such stability problems [14] .…”

Section: Introductionmentioning

confidence: 99%

Graphene‐Mercury‐Graphene Sandwich Electrode for Electroanalysis

et al. 2021

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We present a new class of hybrid 2D electrodes, where mercury is incorporated between two graphene monolayers, prepared by bottom‐up assembly. First, the bottom graphene layer is electrochemically modified leading to the creation of fine mercury nanodroplets of variable size on the graphene surface. Although such electrodes show good sensitivity to heavy metal ions, their stability is limited due to the outgassing of mercury over time. After coverage with a top monolayer, the graphene surface is rendered with the favorable properties of mercury such as the high overpotential for hydrogen evolution, the ability to work at a broader cathodic potential range and higher sensitivity towards heavy metal ions such as Cd2+ and Pb2+. Most importantly, the outgassing of mercury is completely hindered by the top layer, which yields a stable mercury‐like electrode but with a carbonaceous non‐toxic interface. We attribute the favorable properties of the sandwich electrode to the subsurface mercury present below the top graphene sheet, which renders it with new electrochemical properties.

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“…The mercury film coating on the glassy carbon electrode consists of a myriad of tiny mercury droplets; dense and uniform mercury droplets are prerequisites for good electrode performance [7]. The working environment affects the extent of reactions on the electrode surface, and the coating parameters affect the mercury load on the electrode surface and the distribution of the mercury micro-drops.…”

Section: Introductionmentioning

confidence: 99%

Pre-coated mercury film on glassy-carbon electrode for the simultaneous determination of Cu2+, Zn2+, Cd2+, and Pb2+ in water

Pei¹,

Yu²,

Liu³

et al. 2019

Studia UBB Chemia

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A mercury film was pre-coated on glassy-carbon electrodes to improve the precision and detection limit of the electrodes in anodic stripping voltammetry. A mixed solution containing 0.1 mg/l Zn 2+ , 0.01 mg/l Pb 2+ , 0.01 mg/l Cd 2+ , and 0.5 mg/l Cu 2+ was used to investigate the simultaneous detection of these ions by the electrode. The influence of the base solution pH and the accumulation time on the electrochemical reactions of Cu 2+ , Zn 2+ , Cd 2+ , and Pb 2+ were investigated, as well as the effect of the concentration of the film coating solution and the number of mercury coating step on the stripping signals of the four ions. Optimizing the parameters of the pre-coated mercury film improved the precision of the glassy-carbon electrode in evidence. When the base solution pH was 4.68, and the accumulation time was 300 s, the positions of the stripping peaks were optimal, and the peak signals were at a maximum. When the concentration of the film coating solution was 0.03 mol/l HgCl2, and the mercury coating step was repeated three times, the prepared electrode showed a moderately high elution peak with little noise. The optimized electrode demonstrated superior precision and detection limits in the simultaneous detection of Zn 2+ , Cd 2+ , Pb 2+ , and Cu 2+ , compared with the uncoated electrode. The calibration curves were highly linear with determination coefficients (R 2) of 0.9913 (Cu 2+), 0.9939 (Pb 2+), 0.9933 (Cd 2+), and 0.9962 (Zn 2+); the detection limits (µg/l) were 5 for Cu 2+ , 1 for Pb 2+ , 0.1 for Cd 2+ , and 10 for Zn 2+ , and the relative standard deviations obtained from five replicate experiments were 4.1% (Cu 2+), 2.1% (Pb 2+), 2.7% (Cd 2+), and 3.4% (Zn 2+). It is reasonable to suppose that the precision and detection limits of this mercury film electrode may meet the requirements for the simultaneous detection of multiple heavy metal ions in water in the natural environment.

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Voltammetric and microscopical investigation of the properties and behaviors of individual mercury micro-droplets

Cited by 13 publications

References 17 publications

A Fourier Transform-Induced Data Process for Label-Free Selective Nanopore Analysis under Sinusoidal Voltage Excitations

A Fourier Transform-Induced Data Process for Label-Free Selective Nanopore Analysis under Sinusoidal Voltage Excitations

Graphene‐Mercury‐Graphene Sandwich Electrode for Electroanalysis

Pre-coated mercury film on glassy-carbon electrode for the simultaneous determination of Cu2+, Zn2+, Cd2+, and Pb2+ in water

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