Showing papers on "Reference electrode published in 1970"

Chapter IV Redox Potential

Abstract: Publisher Summary Redox potential may be determined as voltage (in volts or millivolts), when an inert noble metal electrode is connected to a reference electrode and both are placed in a solution containing a reversible redox system. This value gives information on the following: (1) the formation of redox potential in cultures of micro-organisms. (2) The order of redox substances in a redox chain (for example, arrangement of enzymes in the respiration chain). (3) The free enthalpy of redox substances, making it possible to describe chemical reactions. The potential difference between the aerated nutrient solution and the metabolically active bacterial culture can be used to perform work and obtain energy. The chapter discusses the measurement of redox potentials, including redox-potential determination with indicator dyes and electrometric redox-potential determinations. If the potential of a nutrient solution is measured and this solution then inoculated, a change of the redox potential to a more negative value indicates the start of growth. The chapter discusses Redox potential of different physiological types of bacteria, including aerobic bacteria, facultative anaerobes, and anaerobic bacteria. The buffering action of a redox substance is dependent on its concentration in the solution. The capacity term for redox potential is the “poising effect” that characterizes the capacity of a system to counteract a variation in potential. An example is the presence of methylene blue (MB) in a culture solution.

Potentiometric microdetermination of phosphate with an ion-selective lead electrode

Abstract: A method for the microdetermination of orthophosphate by direct potentiometric titration with lead perchlorate is described. A lead-selective indicator electrode and a double junction reference electrode are used in conjunction with an expanded-scaleph meter to monitor the emf. Solutions must be buffered atph 8.25 to 8.75. 0.01 to 0.1 mg phosphorus is titrated with 0.005M lead perchlorate, while larger amounts (up to 2.5 mg) are titrated with 0.01M lead perchlorate. Nitrate (up to 100 times the phosphorus content) and sulfate (250 times) do not interfere, while chloride (100 times) and fluoride (133 times) cause slightly high results for phosphorus. The silicate content should not exceed that of phosphorus. Anions forming insoluble lead salts (−logKsp>8) interfere in this determination.

Iridium-iridium oxide electrode for measuring ph of blood and other fluids

Abstract: A WIRE OF IRIDIUM OR IRIDIUM AND ITS NOBLE METAL ALLOYS IS TREATED IN A MANNER THAT MAKES IT USEFUL AS AN ELECTRODE FOR SENSING HYDROGEN ION CONCENTRATION OF PH OF BLOOD OR OTHER FLUID. THE ELECTRODE MAY BE ADMITTED TO A BLOOD VESSEL THROUGH A SMALL CANNULA. VARIATIONS IN THE DIFFERENCE BETWEEN THE POTENTIALS DEVELOPED BY THE NEW ELECTRODE AND A SUITABLE REFERENCE ELECTRODE ARE METERED AND LINEARILY RELATED TO PH CHANGES.

Portable, self-contained system for analyzing biological fluids or the like

Abstract: A completely portable, self-powered system for rapidly and accurately measuring whole blood hematocrit and pH and levels of sodium, potassium, chloride and the other ions in blood and other fluids. The system includes a compact carrying case which contains an aluminum heat block with a glass electrode chamber therein. Individual selective ion electrodes are fitted in the electrode chamber. A reference electrode, a high-impedance electrode switch, a high-impedance solid-state electrometer, a direct readout scale calibrated in pH units and in milliequivalents per liter, and an integral rechargeable power supply are all contained in the carrying case. A heat control unit and a miniature centrifuge along with blood collecting accessories are included in the self-contained system for analyzing biological fluids.

Hydrogen ion selective sensor and electrode therefor

Abstract: A hydrogen ion selective sensor has a sensing electrode with a palladium oxide coated palladium surface element and a reference electrode. A specific hydrogen ion selective sensor has a sensing electrode with a palladium oxide coated palladium surface element, a reference electrode spaced from and electrically insulated from the sensing electrode, an electrically insulating cover surrounding the palladium portion of the sensing electrode and the reference electrode, the cover defining an electrolyte chamber for containing a reference electrolyte therein, and a wick extending outwardly from the chamber adjacent the palladium oxide portion of the sensing electrode. An improved hydrogen ion selective sensing electrode is described which has a palladium oxide coated palladium surface element.

Apparatus for oxygen determination

Abstract: 1,255,417. Electro-chemical analysis. UNITED STATES STEEL CORP. May 6, 1969 [May 7, 1968], No.23128/69. Heading G1N. A probe for determining the oxygen content of liquid steel comprises a zirconia disc 2 fused in an e.g. silica tube 4 with a reference electrode 6 of Cp, Cr 2 O 3 mixture and a Pt-Pt/Rh thermocouple, the Pt wire acting as a lead to the electrode. A second electrode for contacting the molten steel comprises a molybdenum cermet disc 18 in a silica tube 26 and with a platinum lead 22. The two electrode elements are housed in an alumina container tube 16 filled with refractory cement 28, and covered with a copper or brass fusable cap 34 to protect the working faces as the probe is lowered through the slag. A protective tube 36 extends above the top of the melt to protect the wires and upper elements of the probe. Percentage compositions of the electrolyte and the reference electrode are given. Instead of being used as a dipper, the probe may be mounted e. g. in the lining of a tundish.

Method and apparatus for determining both the average corrosion rate, and the pitting tendency, substantially independently of the resistance of the electrolyte

Abstract: The method makes use of three electrodes which are exposed to the corrosive environment, the electrodes being the corroding or test electrode, the reference electrode, and the auxiliary electrode. The corroding electrode is made 10 millivolts positive relative to the reference electrode, and is then made 10 millivolts negative relative thereto. The anodic and cathodic currents which flow through a circuit including the corroding electrode and the auxiliary electrode are then averaged to produce an indication of the general or average corrosion rate, there being no substantial error due to the resistance of the electrolyte. The difference between such anodic and cathodic currents is determined in order to provide the pitting tendency or pitting index of the system. In accordance with a second embodiment of the method, the corroding electrode is forced to be at the same potential as that of the reference electrode. The current which then flows through a circuit including the corroding electrode and the auxiliary electrode is measured by a microammeter and is the pitting tendency of the system. Thereafter, the microammeter is caused to read zero despite the fact that current is passing therethrough, and the corroding electrode is forced to be at a 10 millivolt potential difference from the reference electrode. The reading of such microammeter is then directly proportional to the general or average corrosion rate.

Electrochemical oxygen demand system

Abstract: A method and system for the determination of organic and inorganic waste products present in aqueous samples, the arrangement including cell means for receiving a flow of an aqueous sample therethrough with means for delivering a predetermined quantity of a water soluble electrolyte into said sample prior to passing through said cell. Heating means are provided for maintaining the sample at a predetermined temperature level as it passes through said cell. The cell includes a plurality of space electrodes including a reference electrode, an indicating electrode, and a common electrode in circuit with said reference and indicating electrodes. A first circuit is coupled to the reference and common electrodes and a unipolar electrical signal is impressed thereacross, the magnitude being sufficient for aqueous electrolysis, A second circuit means is coupled to said indicating and common electrodes and delivers a scanning signal of a programmed potential magnitude with periodic increases and decreases in respect to time, the peak magnitude of said scanning signal being less than that required for aqueous electrolysis. Readout means are arranged in series with said indicating and common electrodes for determining the current flow through said second circuit means in response to the scanning signal. The system is also useful for the determination of carbon monoxide in gaseous atmospheres.

Means for electrolytically depositing metal on an object or for anodic oxidation of an object

Abstract: A DEVICE FOR ELECTOLLYTICALLY DEPOSITING METAL ON AN OBJECT OR FOR AND ANODIC OXIDATION OF AN OBJECT IMMERSED IN AN ELECTROLYTIC BATH, HAVING A REFERENCE ELECTRODE IN CONTACT WITH THE ELECTROLYTE IN THE BATH THROUGH AN ION-CONDUCTING CONNECTION TO MEASURE THE POTENTIAL OF THE OBJECT. AN AUXILIARY ELECTRODE IS PLACED CLOSE TO THE OUTLET OF THE ION-CONDUCTING CONNECTION TO SIMULATE THE CONDITIONS AT THE SURFACE OF THE OBJECT. THE POTENTIAL CAN THEN BE MEASURED FROM THE AUXILIARY ELECTRODE.

Electrochemical Meter for Activity Measurements in Natural Environments

Abstract: An electrochemical meter designed for measurements in the marine environment but equally useful in other natural environments is described. Some features of the instrument are (1) all input channels are high impedance; (2) up to 11 reading electrodes can be monitored from one reference electrode; (3) voltages are measured with respect to solution ground; (4) a null balance circuit option; (5) an accuracy of better than 1 mV. With suitable operative ion‐selective electrodes, the instrument can monitor (a) operational activities, (b) activity ratios, (c) solubility products, or (d) states of saturation.

Method of using self-compensating electrode system

Abstract: AN ELECTRODE TYPE SENSING DEVICE WHICH EMPLOYS TWO SEPARATED MEASURING ELECTRODES OF THE SEME TYPE AND A COMMON GROUND FOR MAKING ELECTRODE POTENTIAL DETERMINATIONS SUCH AS DISSOLVED OXYGEN AND PH MEASUREMENT IN A LIQUID. IN ONE EMBODIMENT, ONE OF THE MEASURING ELECTRODES IS DISPOSED IN A STANDARD SOLUTION WHICH IS PLACED IN BUT SEALED FROM THE MATERIAL TO BE TESTED EXCEPT FOR AN ELECTRICAL COMMONICATION. IN AN ALTERNATIVE EMBODIMENT, BOTH MEASURING ELECTRODES ARE PLACED IN A MATERIAL, THE ION OR MOLECULAR CONTENT OF WHICH IS TO BE MEASURD BUT, AT A SUBSTANTIAL DISTANCE FROM EACH OTHER AND WITH A COMMON GROUND. BOTH EMBODIMENTS ELIMINATE THE PREVIOUS PROBLEM OF TEMPERATURE AND OTHER ENVIRONMENTAL ASPECTS WHICH EFFECTS A REFERENCE ELECTRODE AND THE MEASURING ELECTRODE IN A DIFFERENT MANNER.

Microdetermination of fluorine in organic compounds containing phosphorus and in hexafluorophosphates

Abstract: A method for the microdetermination of fluorine in organic compounds containing phosphorus is described. After combustion in a Vycor flask, the species containing phosphorus are oxidized to orthophosphate with alkaline hypobromite. Phosphate is adsorbed on zinc oxide which need not be removed prior to titration of the fluoride. Fluoride is titrated potentiometrically with 0.02M lanthanum(III) in 50% ethanol solution at pH 5–7. A fluoride ion-specific indicator electrode and a calomel reference electrode are used in conjunction with an expanded-scale pH meter to monitor the emf. This method can also be used for the determination of total fluorine in inorganic hexafluorophosphates. For the more stable compounds such as potassium hexafluorophosphate, a combustion aid (paraffin) must be added to promote combustion.

Measuring electrode for measuring of ions in solutions

Abstract: A MEASURING ELECTRODE FOR MEASURING IONS IN SOLUTION COMPRISES AN ELECTRICALLY INSULATING CYLINDRICAL CASING WHICH CONTAINS A GLASS OR PLASTICS CYLINDER HAVING OPEN TOP AND BOTTOM ENDS AND A TRANSVERSE PARTITION WALL, AND A DETACHABLE ELECTRODE BASE CARRYING THE ION SELECTIVE MEMBER AND CLOSING THE BOTTOM END OF SAID CYLINDER TO FORM A HOLLOW SPACE WITHIN THE CYLINDER BETWEEN SAID PARTITION WALL AND THE ELECTRODE BASE ADAPTED TO CONTAIN THE REFERENCE SOLUTION. AN INTERNAL REFERENCE ELECTRODE IS IMMERSED IN THE SOLUTION AND SEALINGLY LEADS THROUGH SAID TRANSVERSE PARTITION WALL AND EXTENDS TO THE TOP OF THE CASING WHERE IT IS CONNECTED TO JUNCTION MEANS. MEANS ARE PROVIDED TO ENABLE AN EASY EXCHANGE OF THE ELECTRODE BASE OF THE REFERENCE SOLUTION AND OF THE ION-SELECTIVE MATERIAL.