-
Sensors (Basel, Switzerland) 2011Potentiometric sensors are attractive tools for the fabrication of various electronic tongues that can be used in wide area of applications, ranging from foodstuff... (Review)
Review
Potentiometric sensors are attractive tools for the fabrication of various electronic tongues that can be used in wide area of applications, ranging from foodstuff recognition to environmental monitoring and medical diagnostics. Their main advantages are the ability to modify their selectivity (including cross-sensitivity effects) and the possibility of miniaturization using appropriate construction methods for the transducer part (e.g., with the use of solid-state technology). In this overview various examples of the design, performance, and applications of potentiometric electronic tongues are presented. The results summarize recent research in the field conducted in the Department of Microbioanalytics, Warsaw University of Technology (WUT).
Topics: Biosensing Techniques; Electrodes; Electronics; Neural Networks, Computer; Potentiometry; Principal Component Analysis
PubMed: 22163870
DOI: 10.3390/s110504688 -
Sensors (Basel, Switzerland) Sep 2023For the first time, a prototype of a portable device for the potentiometric determination of antioxidant capacity based on a new measurement principle is proposed. A...
For the first time, a prototype of a portable device for the potentiometric determination of antioxidant capacity based on a new measurement principle is proposed. A feature of the approach is the use of an electrochemical microcell with separated spaces and two identical electrodes with immobilized reagents. An antioxidant solution is introduced into one half-cell, and the antioxidants interact with the reagents. The other half-cell contains only reagents. The potential difference between the electrodes is due to the change in the ratio of the oxidized and reduced form of the reagents, which occurs as a result of the reaction with the antioxidants in one of the half-cells and is related to their concentration. The range of linearity of the microcell with immobilized reagents is 40-4000 μM-eq, and the limit of detection is 20 μM-eq. The device was successfully tested in the analysis of standard antioxidant solutions. The recoveries were (92-113)%, and the relative standard deviation did not exceed 15%. A good correlation was found between the data obtained by the approach and the potentiometric method in a macrocell for fruit juice analysis. Pearson's coefficient for the obtained experimental data was 0.9955. The proposed portable device is promising and can be used in field conditions.
Topics: Antioxidants; Potentiometry; Electrodes
PubMed: 37765901
DOI: 10.3390/s23187845 -
Frontiers in Bioscience (Elite Edition) Jan 2011Based on biological molecules combined with nanostructured components, the news generations of electrochemical biosensors can employ different transducers... (Review)
Review
Based on biological molecules combined with nanostructured components, the news generations of electrochemical biosensors can employ different transducers (potentiometric, amperometric and impedimetric) converting the chemical information into a measurable amperometric signal. Following this contemporary theme, our main focus in this review is to discuss different methodologies for application in biosensing, whose signal transduction is based on electrochemical principles. We apply a discussion on recent trends involving different nanostructured materials, but without daring to contemplate all nanomaterials incessantly cited in literature, which leads us to believe that this moment is an unprecedented revolution in the preparation of electrochemical biodevices. Besides, some structures of bio-nano interface and different electrochemical biosensors involved in diagnosis systems are also discussed. We outline in several parts of the report how nanoscience technologies are emerging in diagnostic medicine, as well as convergence of electrochemistry and bio-nanoscience. Our hopes for this review are that it can help different categories of researchers to understand the broad application area of electrochemistry and bioelectrochemistry, in order to detecting several types of diseases and biological phenomena.
Topics: Biosensing Techniques; DNA; Electrochemical Techniques; Immunoassay; Nanostructures; Nanotechnology; Potentiometry; Transducers
PubMed: 21196343
DOI: 10.2741/e278 -
The Quarterly Journal of Nuclear... Sep 2008A series of chemical in vitro assays are described to provide a rapid initial assessment of the in vivo stability and biological behaviour of potential new copper(II)... (Review)
Review
A series of chemical in vitro assays are described to provide a rapid initial assessment of the in vivo stability and biological behaviour of potential new copper(II) based radiopharmaceutical agents. Chemical challenges using an excess of cysteine, glutathione (GSH) and histidine, which are models of S- and N-donor molecules found in vivo, are used to provide a measure of the potential for loss of the copper(II) ion from the radiopharmaceutical as a result of ligand dissociation. In addition, thiol containing molecules such as cysteine and GSH provide a redox challenge, whereby the copper(II) complex may be reduced to give a copper(I) species. The stability of the copper(I) species toward oxidation, protonation, and ligand dissociation may be crucial in determining the biodistribution, the biological half-life and excretion mechanisms of a potential radiopharmaceutical. Further evaluation of the redox stability is assessed using the ubiquitous biological reductant ascorbic acid. The relative stability of a complex with respect to ligand dissociation in human serum provides one of the most important experiments assessing the potential of a complex to be used in vivo. Further challenge experiments with serum proteins such as thioredoxin and serum albumin can be used to provide more detailed information on the probable fate of the complex in serum. Evaluation of complex stability and speciation over a range of pH values may also be used to obtain information on potential biodistribution.
Topics: Blood Proteins; Copper; Crystallography, X-Ray; Cysteine; Glutathione; Histidine; In Vitro Techniques; Ions; Models, Chemical; Molecular Conformation; Oxidation-Reduction; Pharmaceutical Preparations; Potentiometry; Radiopharmaceuticals; Spectrophotometry; Sulfhydryl Compounds
PubMed: 18551094
DOI: No ID Found -
Ground Water Sep 2021
Topics: Groundwater; Potentiometry
PubMed: 34272877
DOI: 10.1111/gwat.13123 -
Lab on a Chip May 2017The demand for wearable sensors has grown rapidly in recent years, with increasing attention being given to epidermal chemical sensing. Here, we present the first...
The demand for wearable sensors has grown rapidly in recent years, with increasing attention being given to epidermal chemical sensing. Here, we present the first example of a fully integrated eyeglasses wireless multiplexed chemical sensing platform capable of real-time monitoring of sweat electrolytes and metabolites. The new concept has been realized by integrating an amperometric lactate biosensor and a potentiometric potassium ion-selective electrode into the two nose-bridge pads of the glasses and interfacing them with a wireless electronic backbone placed on the glasses' arms. Simultaneous real-time monitoring of sweat lactate and potassium levels with no apparent cross-talk is demonstrated along with wireless signal transduction. The electrochemical sensors were screen-printed on polyethylene terephthalate (PET) stickers and placed on each side of the glasses' nose pads in order to monitor sweat metabolites and electrolytes. The electronic backbone on the arms of the glasses' frame offers control of the amperometric and potentiometric transducers and enables Bluetooth wireless data transmission to the host device. The new eyeglasses system offers an interchangeable-sensor feature in connection with a variety of different nose-bridge amperometric and potentiometric sensor stickers. For example, the lactate bridge-pad sensor was replaced with a glucose one to offer convenient monitoring of sweat glucose. Such a fully integrated wireless "Lab-on-a-Glass" multiplexed biosensor platform can be readily expanded for the simultaneous monitoring of additional sweat electrolytes and metabolites.
Topics: Biosensing Techniques; Electrolytes; Equipment Design; Eyeglasses; Female; Humans; Lactic Acid; Male; Monitoring, Physiologic; Potentiometry; Sweat; Wireless Technology
PubMed: 28470263
DOI: 10.1039/c7lc00192d -
ACS Sensors Oct 2021Potentiometric sensors induce a spontaneous voltage that indicates ion activity in real time. We present here an advanced self-powered potentiometric sensor with memory....
Potentiometric sensors induce a spontaneous voltage that indicates ion activity in real time. We present here an advanced self-powered potentiometric sensor with memory. Specifically, the approach allows for one to record a deviation from the analyte's original concentration or determine whether the analyte concentration has surpassed a threshold in a predefined time interval. The sensor achieves this by harvesting energy in a capacitor and preserving it with the help of a diode. While the analyte concentration is allowed to return to an original value following a perturbation over time, this may not influence the sensor readout. To achieve the diode function, the sensor utilizes an additional pair of driving electrodes to move the potentiometric signal to a sufficiently high base voltage that is required for operating the diode placed in series with the capacitor and between the sensing probes. A single voltage measurement across the capacitor at the end of a chosen time interval is sufficient to reveal any altered ion activity occurring during that period. We demonstrate the applicability of the sensor to identify incurred pH changes in a river water sample during an interval of 2 h. This approach is promising for achieving deployable sensors to monitor ion activity relative to a defined threshold during a time interval with minimal electronic components in a self-powered design.
Topics: Electrodes; Electronics; Potentiometry
PubMed: 34582164
DOI: 10.1021/acssensors.1c01273 -
Sensors (Basel, Switzerland) Nov 2023In the present work, potentiometric sensors with polymer membranes used for chlorhexidine (CHXD) determination were developed. The polymer membranes were plasticized...
In the present work, potentiometric sensors with polymer membranes used for chlorhexidine (CHXD) determination were developed. The polymer membranes were plasticized with bis(2-ethylheksyl)sebacate (DOS) or 2-nitrophenyloctyl ether (-NPOE). The active compounds used in the membrane were cyclodextrins, crown ethers, and ion exchangers. The best-constructed electrode was based on neutral heptakis(2,3,6-tri-O-benzoyl)--cyclodextrin with lipophilic salt (KTpClBP)-potassium tetrakis(4-chlorophenyl) borate-dissolved in plasticizer, DOS. The presented electrode is characterized by an average cationic slope of 30.9 ± 2.9 mV decade within a linear range of 1 × 10 to 1 × 10 mol × L, while the value of the correlation coefficient is 0.9970 ± 0.0026. The response time was about 5 s when increasing the sample concentration and about 10 s when diluting the sample. The electrode potential is independent of the pH within a range of 4.0-9.5. The polymeric membrane sensor was successfully applied for assays of chlorhexidine digluconate in pure samples and pharmaceutical samples. The relative error from three replicate measurements was determined to be 1.1%. and the accuracy was RSD = 0.3-1.1%.
Topics: Chlorhexidine; Membranes, Artificial; Electrodes; Potentiometry; Polymers; Hydrogen-Ion Concentration
PubMed: 38067881
DOI: 10.3390/s23239508 -
Molecules (Basel, Switzerland) Nov 2022Stability-indicating methods are awesome tools to ensure the safety and efficacy of active pharmaceutical ingredients (APIs). An accurate comparative study involving the...
Stability-indicating methods are awesome tools to ensure the safety and efficacy of active pharmaceutical ingredients (APIs). An accurate comparative study involving the use of potentiometric sensors for the determination of bromazepam (BRZ) in the presence of its main product of degradation and impurity was performed by the fabrication of two membrane electrodes. A screen-printed electrode (SPE) and a solid-contact glassy carbon electrode (SCE) were fabricated and their performance optimized. The fabricated sensors showed a linear electrochemical response in the concentration range 1.0 × 10 M to 1.0 × 10 M. The electrodes exhibited Nernstian slopes of 59.70 mV/decade and 58.10 mV/decade for the BRZ-SPE and BRZ-SCE membrane electrodes, respectively. The electrochemical performance was greatly affected by the medium pH. They showed an almost ideal electrochemical performance between pH 3.0 and pH 6.0. The fabricated membranes were applied successfully for the quantification of BRZ in the presence of up to 90% of its degradation product. Moreover, a successful application of the fabricated electrodes was performed for the sensitive and selective quantification of BRZ in its tablet form without any pretreatment procedure.
Topics: Bromazepam; Electrodes; Potentiometry; Carbon; Tablets
PubMed: 36364443
DOI: 10.3390/molecules27217616 -
Biosensors & Bioelectronics Apr 2022The field of electrochemical biosensors has been dominated by amperometric and voltammetric sensors; however, these are limited greatly in their signal dependence on...
The field of electrochemical biosensors has been dominated by amperometric and voltammetric sensors; however, these are limited greatly in their signal dependence on electrode size. Open circuit potentiometric sensors are emerging as an alternative due to their signal insensitivity to electrode size. Here, we present a second-generation biosensor that uses a modified chitosan hydrogel to entrap a dehydrogenase or other oxidoreductase enzyme of interest. The chitosan is modified with a desired electron mediator such that in the presence of the analyte, the enzyme will oxidize or reduce the mediator, thus altering the measured interfacial potential. Using the above design, we demonstrate a swift screening method for appropriate enzyme-mediator pairs based on open circuit potentiometry, as well as the efficacy of the biosensor design using two dehydrogenase enzymes (FADGDH and ADH) and peroxidase. Using 1,2-naphthoquinone as the mediator for FADGDH, dynamic ranges from 0.1 to 50 mM glucose are achieved. We additionally demonstrate the ease of fabrication and modification, a lifetime of ≥28 days, insensitivity to interferents, miniaturization to the microscale, and sensor efficacy in the presence of the enzyme's natural cofactor. These results forge a foundation for the generalized use of potentiometric biosensors for a wide variety of analytes within biologically-relevant systems where oxygen can be an interferent.
Topics: Biosensing Techniques; Electrodes; Glucose; Oxygen; Potentiometry
PubMed: 35032843
DOI: 10.1016/j.bios.2021.113888