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Topic: Redox indicator

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Related Topics

Indicator

Redox titration

Titration

Reducing agent

Electrochemistry

Complexometric titration

Isothermal titration calorimeter

Oxidizing agent

Spectroscopy

United States Patent: 5,264,348 Accordingly, the indicator dye preferably is a redox indicator that undergoes a color transition upon conversion from its reduced form to its oxidized form by the interaction between the predetermined analyte and the redox mediator. The indicator dye included in the indicator reagent composition is limited only in that the indicator dye is capable of undergoing a detectable response, and preferably a chromogenic response, in the presence of a predetermined analyte and a redox mediator, such as an oxidase-peroxidase couple or a hydroperoxide. The indicator reagent composition of the present invention essentially eliminates the primary interfering affects of ascorbic acid present in the test sample and the secondary interfering affects attributed to the metal ion complex that is included in the indicator reagent composition to interact with the ascorbic acid. spore.patentmatrix.com /Projects/WNCCTC/BOS/5264348.html

Redox Theory Redox values are determined by measuring the potential difference between an inert indicator electrode in contact with the solution and a stable reference electrode connected to the solution by a salt bridge. The redox potential measures the tendency for a solution to either gain or lose electrons when it is subject to change by introduction of a new species. Although measurement of the redox potential in aqueous samples is relatively straightforward, many factors limit its interpretation, such as irreversible reactions, slow electrode kinetics, non-equilibrium, presence of multiple redox couples, electrode poisoning, small exchange currents and inert redox couples. www.ionode.com.au /Techorp.html

FDEP - Wetland Evaluation and Delineation: Hydric Soils Redox concentrations including iron and manganese masses (reddish mottles) and/or pore linings are required in soils with matrix colors of 4/1, 4/2, and 5/2. Redox depletions should have associated microsites redox concentrations that occur as Fe pore linings or masses within the depletion(s) or surrounding the depletion(s). This indicator commonly occurs in hydric Spodosols; however, the identification of a spodic horizon is not required. www.dep.state.fl.us /WATER/wetlands/delineation/soilwatr.htm

Hydric Soils Technical Note 4 NRCS Soils The minimum expression of one indicator may overlap with the maximum expression of another; an indicator may occur in the wettest of hydric soils in one region of the country and that same indicator in the driest of hydric soils in another part of the country. The Field Indicators are available on the internet and users are encouraged to cut and paste the document any way they find most useful. As the Field Indicators are refined regionally, it is anticipated that these types of scenarios will be described and incorporated. soils.usda.gov /use/hydric/ntchs/tech_notes/note4.html

Redox indicator - Wikipedia, the free encyclopedia A redox indicator (also called an oxidation-reduction indicator or a potentiometric indicator) is an indicator that undergoes a definite colour change at a specific oxidation potential. This page was last modified 01:52, 5 May 2005. en.wikipedia.org /wiki/Redox_indicator

General Chemistry Online: Glossary: Redox reactions A blood-red complex of Fe ion with 1,10-phenanthroline, used as a redox indicator Redox reactions always involve a change in oxidation number for at least two elements in the reactants. An organic molecule that has reduced and oxidized forms with different colors; interconversion of the reduced and oxidized forms of the indicator must be reversible. antoine.frostburg.edu /chem/senese/101/redox/glossary.shtml

redox indicator on GlobalSpec Fodor, A. Suteu: Decamolibdodivanadoarsenic Acid a New Reversible Redox Indicator.. Indicators and Comparators (66 companies) Indicators and comparators measure where the linear movement of a precision spindle or probe is amplified. Temperature Indicator / Thermometer Thermocouple temperature indicator with Dual resolution 1 deg or 0.1 deg with deg F & deg C capabilities high temperature range - 200 to 2000 deg f with clip on case and max hold features. www.globalspec.com /industrial-directory/redox_indicator

WRHSRC Research Brief #1 - Field Tools for Measuring Redox Potential The indicator is exposed to the sample in the flow cell and the adsorption spectra are measured by passing light through the cell. Bonding the indicator to the gel-based film was critical – the bond prevents the indicator from attaching to other solids in the sample. Second, the redox conditions of the soil or groundwater samples must be measured without exposure to oxygen since that exposure would change the sample’s redox condition. wrhsrc.oregonstate.edu /briefs/brief_1.htm

Learn more about Titration in the online encyclopedia. In simple acid - base titrations a pH indicator may be used, such as phenolphthalein, which turns (and stays) pink when a certain pH is reached or exceeded. Many methods can be used to indicate the endpoint of a reaction; titrations often use visual indicators (the reactant mixture changes colour). The indicator should change colour as the titrant is added, but then quickly return to its original colour. www.onlineencyclopedia.org /t/ti/titration.html

General Chemistry Online: FAQ: Redox reactions: How does starch indicate iodine? It can also be used as a general redox indicator: when there is excess oxidizing agent, the complex is blue; when there is excess reducing agent, the I The complex is very useful for indicating redox titrations that involve iodine because the color change is very sharp. What properties of starch (given its chemical structure) allow it to be used as an indicator? antoine.frostburg.edu /chem/senese/101/redox/faq/starch-as-redox-indicator.shtml

Titrations Some indicators react with other components of the mixture that are effected by the titrant or titrand. For instance there are indicators that react with calcium ions in water to form a colored complex. The endpoint for phenolphthalein is in the buffer region of the plot. v.d.singleton.home.att.net /genchem/titratns.htm

Metrohm UK Selection of the indicator electrode depends on the nature of the titration reaction and, in ideal situations, should only respond to the ion being measured. In potentiometric titration the zero current potential changes during the titration and this is measured at the indicator electrode. Of the various indication methods available, potentiometric is the main and most suitable for automated titration's because of its versatility. www.metrohm.ie /bt_titration.asp

Molybdenum in sediments as an indicator of marine redox conditions in the geological past Molybdenum in sediments as an indicator of marine redox conditions in the geological past Mo isotope fractionation is a redox proxy for the paleoatmosphere and -oceans. Wille’s project focuses on (a) the theory of Mo fractionation, and (b) a detailed Mo study of black shales through the entire stratigraphy of the early Proterozoic Transvaal Supergroup (2.6 - 2.1 Ga), which straddles the period in which the atmosphere became oxygenated. www.researchportal.ch /unibe/abstracts/A_831.html

these_body.html Potentiometric electrodes for redox titrations are commonly made from platinum, which generally acts as an indicator of the activity ratio of a redox couple. Indicators are often added to the analyte solution in order to provide an observable physico-chemical change (the end-point) at or near the equivalence point. Depending on the chemical reaction in progress, it is possible to identify precipitation, complexometric, redox and neutralisation titrations. www.unige.ch /cyberdocuments/unine/theses2000/GuenatO/these_body.html

Chapter 3. Thiamin, riboflavin, niacin, vitamin B6, pantothenic acid and biotin Indicators used to estimate niacin requirements are urinary excretion, plasma concentrations of metabolites, and erythrocyte pyridine nucleotides. Indicators used to estimate thiamin requirements are urinary excretion, erythrocyte transketolase activity coefficient, erythrocyte thiamin, blood pyruvate and lactate, and neurologic changes. Indicators used to estimate riboflavin requirements are urinary flavin excretion, erythrocyte glutathione reductase activity coefficient, and erythrocyte flavin. www.fao.org /DOCREP/004/Y2809E/y2809e09.htm

Indicators The transition point of an indicator is defined as the point at which the acid and alkaline forms of the indicator exist in equal concentrations. Indicators are usually organic compounds which change color in relation to the concentration of hydrogen ions. One of the properties of indicators is that they do not change color exactly at one pH value, but within a wide pH range. www.sigmaaldrich.com /Area_of_Interest/Analytical__Chromatography/Titration/Indicators.html

Nikivita Instruments -- products The first analog input is suitable for connecting a pH combination electrode, or a glass and reference electrode (also antimony), or a redox combination electrode, or a metal and reference electrode. The 2-wire transmitter is intended for linking a pH or redox combination electrode with plug connection to indicators/controllers with an active 4-20 mA input. A conventional coaxial cable is sufficient as connection between the transmitter and the indicator. www.nikivita.com /prodviewer.asp?cat_id=14

indicator-plate Although indicator plates continue to be a part of diagnostic kits, their use has expanded dramatically in recent years. In many laboratories today, indicator plates are being used in studies on bacterial gene regulation, recombination and chromosome structure. Indicator plates have been in use since the early days of bacteriology. rothlab.ucdavis.edu /protocols/indicator-plates.html

color change pH acid base and metal ion indicators The indicator is stable for at least 12 months when stored in a polythene bottle and in the dark. These types of indicators consist of either a mixture of two indicators or a mixture of an indicator and an inert dye. The saturated supernatant is used as the indicator. delloyd.50megs.com /custom.html

OXYGEN RELEASE FROM PLANT ROOT SYSTEMS IN CONSTRUCTED WETLANDS We used an agar medium containing a redox indicator, as well as microelectrode measurements of oxygen gradients near roots to compare radial oxygen loss (ROL) from eight species: Acorus calamus, Iris pseudoacorus, Juncus effusus, Phalaris arundinacea, Pontideria cordata, Schoenoplectus tabernaemontani, Typha latifolia, and Zea maize as a non-wetland control. Some species could oxidize the redox indicator in the agar medium, but did not produce oxygen gradients that could be detected with the microelectrode. For example, when grown in drained conditions, Acorus calamus had the highest proportions of coarse roots oxidizing the redox indicator, and the highest oxygen flux detected by the microelectrode method. www.caf.wvu.edu /wvafes/projects2001/PSS_WVA00138.htm

Practical Guidelines However, indicator is added ONLY near the end-point, ie, when the red-brown colour of iodine fades to pale yellow(starch will turn the mixture dark blue); Reason : Reagents used for redox titrations are usually unstable and may oxidise on exposure to air. Sodium thiosulphate and iodine - starch used as indicator. jazilahothman.tripod.com /sitebuildercontent/practical/redox.html

WQM-Redox Instrument The WQM-Redox unit is intended for continuous operation to monitor the Redox in activated sludge plants and produce the appropriate control or warning signals. The Redox measurement is based on the metal electrode, which employs Platinum. The complete measuring electrode is made by using with the Platinum indicator a standard pH reference electrode. www.manook.freeserve.co.uk /wqm-redox.html

A Reading Guide and Homework List for Chapters 16 To be a successful indicator the value of the solution property that changes must be associated with a property of the indicator. of the indicator, in complex titrations the p(metal ion) is associated with the K Because of the differences in their reduction potentials and the conditions under which they may be successfully applied (such as acidic or basic), they each have applications for which they are preferred. mulliken.chem.hope.edu /~seymour/analyt98/ch_16.html

Redox/algae control Expensive Redox meters/ozone equipment can be had if you wish but a simple observational account using something like H2O2 may be enough to convince me or others that this idea may be deeper than appears. I used this as an indicator for health at one point and perhaps I was on to something but couldn't put it together back then. James says: >Well then, if that's the case, a small Ozone generator would raise the redox >potential of the water and the ozone, after it has worked it's magic on the >algae spores, would decompose into perfectly harmless oxygen. fins.actwin.com /aquatic-plants/month.200007/msg00023.html

Evaluation of a Scanner-Assisted Colorimetric MIC Method for Susceptibility Testing of Gram-Negative Fermentative Bacteria -- Rahman et al. 70 (4): 2398 -- Applied and Environmental Microbiology Evaluation of redox indicators and the use of digital scanners and spectrophotometer for quantification of microbial growth in microplates. Checkerboard titration of bacterial growth in relation to inoculum size and concentration of TTC in a microplate, where each row shows decreasing concentrations of indicator and each column shows decreasing inoculum size. It may be argued that the influence of the indicator on the aem.asm.org /cgi/content/full/70/4/2398

Oscillating reactions and chemical waves by G. Dupuis and N. Berland - Lycée Faidherbe The oscillations of concentrations are accompanied by a variation of the average redox potential of the solution during the experiment. The variation of potential leads to a modification in the colour of the indicator : the ferroin, which is a complex between Fe (II) and the 1, 10-phenantrolin (ophen). In a gel, after the addition of starch (an indicator), these research workers saw some regular rows of task in the reactor as Turing had predicted them. www.faidherbe.org /site/cours/dupuis/oscil.htm

Peroxides in Protein Sequencing Solvents According to the manufacturer, the strips contain peroxidase, which transfers oxygen from peroxides to an organic redox indicator, producing a blue-colored oxidation product on the strip. For aqueous solutions, solvent A is spotted on the indicator zone of the test strip and compared to the standard strip's color scale after 15 secs. The strips are 0.6 cm x 7.5 cm long with an indicator area of 0.6 cm2 and a working pH range of 2-12. www.abrf.org /ABRFNews/1995/June1995/jun95peroxides.html

Colour-Tag-Protein Alcohol dehydrogenase Thereby changes in the redox state are coupled with colour changes. In contrat, the variants of CTP depend on specific redox substrates to change the redox state. The high stability and the electro-chemical properties of CTP allow applications in Bio-Chips for automated detection and analysis of substrates and their redox states. www.x-zyme.com /ctp.html

JUMO - Analytical Measurement Technology Standard cables for pH and redox electrodes, compensation thermometers and glass conductivity cells pH and redox combination electrodes JUMO tecLine pH/ JUMO tecLine Rd Ion-Selective Sensor for measuring ammonia Indicator / controller for analytical measurement dTRANS Az 01 in 96 x 48 mm format www2.jumo.de /gb/produkte/PL20/PL20.html

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