Search results for "microbalance"

Identification of high-affinity phage-displayed VH fragments by use of a quartz crystal microbalance with dissipation monitoring

2021

10 Pág. Departamento de Tecnología de Alimentos​​

EIS and Ac-electrogravimetry study of PB films in KCl, NaCl, and CsCl aqueous solutions

2003

Prussian Blue films have been studied by means of ac-electrogravimetry, electrochemical impedance spectroscopy, and electrochemical quartz crystal microbalance in different aqueous salt solutions. Impedance data was interpreted in terms of a model based on a potential drop at the electrode/film interface and a potential drop at the film/solution interface. Quantitative results obtained by the fitting of impedance and ac-electrogravimetry allow to conclude that the main contribution to the potential drop at the film/solution interface is due to the dehydration-hydration process of cations on entering or leaving the film.

Validation of the mass response of a quartz crystal microbalance coated with Prussian Blue film for ac electrogravimetry

2000

Prussian Blue (PB) films have been considerably studied for many research applications such as electrochromic material development, new material for batteries, etc. Many analytical techniques were employed for examining PB electrochemical behaviour in solution and the quartz crystal microbalance (QCM) used in the alternative regime (ac electrogravimetry) appeared as an attractive in situ mass sensor due to its low cost and its high mass sensitivity. Unfortunately, the validity of the common Sauerbrey equation was questionable with these films or in other terms if the QCM was used as a pure mass sensor. In this work PB film is examined through acoustic measurements and the response can be in…

Identification of Processes Associated with Different Iron Sites in the Prussian Blue Structure by in Situ Electrochemical, Gravimetric, and Spectros…

2012

The physicochemical properties of Prussian blue films are strongly dependent on the ratio Fe3+/Fe2+ in the structure. This ratio can be modulated by electrochemical techniques such as cyclic voltammetry, and some information about physicochemical properties can be extracted from in situ auxiliary techniques. Prussian blue films have been studied by the use of in situ vis–NIR spectroscopy, quartz crystal microbalance, and electrochemical techniques (cyclic voltammetry and electrochemical impedance spectroscopy). By cyclic voltammetry + absorbance derivative curves + mass derivative curves, it has been possible to identify at least three different processes during the reduction of Prussian bl…

Study of Prussian Blue (PB) films by ac-electrogravimetry: influence of PB morphology on ions movement

2000

The electrochemical response of Prussian Blue films in NaCl solutions was studied. It was proved that the stability with cycling of PB films increased when these films are covered with a Nafion® membrane. This fact allows PB films to be studied in NaCl solutions under steady state conditions by impedance spectroscopy and ac-electrogravimetry. A model, which can explain the differences between the electrochemical behaviour of amorphous PB films and crystalline PB films in NaCl solutions, is proposed. This model is based on the hypothesis of a partial dehydration of the sodium ions before the electrochemical reactions take place, allowing the transport of sodium ions through the zeolitic chan…

Electrochemical Quartz Crystal Microbalance Study of Copper Electrochemical Reaction in Acid Medium Containing Chlorides

2006

Copper electrodissolution and electrodeposition were studied by means of gravimetric quartz crystal microbalance and electric cyclic voltammetry combined measurements. Relevant information on the mechanism of these electrochemical processes is provided by the analysis of experimental data and particularly of the mass change per charge unit. The copper electrodeposition and electrodissolution take place by means of two consecutive monoelectronic transfers where the anion participation in the reaction mechanism is specified. Besides, it is proved that the presence of molecular oxygen in the solution contributes to the formation of a passive layer on the surface of the metallic copper deposit.

Anodic Dissolution of Nickel across Two Consecutive Electron Transfers

2007

The analysis of the electrochemical quartz crystal microbalance and electrochemical impedance spectroscopy results are consistent with a nickel electrodissolution process limited by the passage of Ni(I) to Ni(II), when chloride ions are present in the acid sulfate medium, or by the passage of Ni(II) to Ni 2+ in solution, in absence of chloride. This interpretation allows an explanation of the potential evolution of Fdm/dQ values in both experimental conditions by assuming the formation of a new phase on the electrode surface with a gel-like structure placed between the metal and the solution. Ni(I) surface concentration is calculated from the instantaneous mass/charge Fdm/dQ values.

Cover Picture: Solvent-Adaptive Behavior of Oligospirobifluorenes at the Surface of Quartz Crystal Microbalances-A Conformational Process (ChemPlusCh…

2017

Scrutiny of annexin A1 mediated membrane-membrane interaction by means of a thickness shear mode resonator and computer simulations.

2004

The dissipational quartz crystal microbalance (D-QCM) technology was applied to monitor the adsorption of vesicles to membrane-bound annexin A1 by simultaneously reading out the shifts in resonance frequency and dissipation. Solid-supported membranes (SSMs) composed of a chemisorbed octanethiol monolayer and a physisorbed 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoserine monolayer were immobilized on the gold electrode of a 5 MHz quartz plate. Adsorption and desorption of annexin A1 to the SSM was followed by means of the QCM technique. After nonbound annexin A1 was removed from solution, the second membrane binding was monitored by the D-QCM t…

Partially Reversible Adsorption of Annexin A1 on POPC/POPS Bilayers Investigated by QCM Measurements, SFM, and DMC Simulations

2005

The kinetics of annexin A1 binding to solid-supported lipid bilayers consisting of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoserine (POPS; 4:1) has been investigated as a function of the calcium ion concentration in the bulk phase. Quartz crystal microbalance measurements in conjunction with scanning force microscopy, fluorescence microscopy, and computer simulations indicate that at a given Ca2+ concentration annexin A1 adsorbs irreversibly on membrane domains enriched in POPS. By contrast, annexin A1 adsorbs reversibly on the POPC-enriched phase, which is composed of single POPS molecules embedded within a POPC matrix. The overall are…