MODERN ELECTROCHEMISTRY

THE HISTORY OF ELECTROCHEMISTRY IS BRIEFLY OUTLINED STARTING WITH MICHAEL FARADAY. BECAUSE ELECTROCHEMICAL MEASUREMENTS OFFER ACCURACY, PRECISION, AND AN EASE OF AUTOMATION, THEY HAVE PROVIDED THE BASIS FOR MANY OF THE NEW AND IMPROVED TECHNIQUES. HIGHLY REFINED WAYS TO MAKE ELECTRICAL MEASUREMENTS PERMIT RELIABLE DETERMINATIONS AT THE SUBMICROAMPERE AND MICROVOLT RANGE. THE SIMPLEST ELECTROCHEMICAL TECHNIQUE INVOLVES CURRENT PASSAGE THROUGH A SOLUTION FOR EXHAUSTIVE ELECTROLYSIS. ELECTRICAL MEASUREMENTS ARE EXCELLENT INDICATORS IN ALL AREAS OF TITRIMETRY. ELECTROCHEMICAL SENSORS ARE BASED UPON POTENTIOMETRIC, CONDUCTOMETRIC, OR AMPEROMETRIC PRINCIPLES AND EACH HAS ITS USE IN A GIVEN SITUATION. CLASSICAL POLAROGRAPHY USES A DROPPING MERCURY ELECTRODE AND PRODUCES CURRENT-VOLTAGE CURVES WITH RESPECT TO A REFERENCE ELECTRODE. MODIFIED POLAROGRAPHIC INSTRUMENTS USING PULSING TECHNIQUES, SOPHISTICATED CIRCUITRY, OR HIGHLY STABILIZED ELECTRODE SYSTEMS HAVE INCREASED MEASUREMENT ACCURACY AND LOWERED DETECTION LIMITS BY AN ORDER OF MAGNITUDE. A RECENT INNOVATION IS THE SINGLE, RAPID VOLTAGE-SCAN DURING A SELECTED PART OF THE GROWTH CYCLE OF A SINGLE DROP RATHER THAN OVER A SERIES OF DROPS. THE CURRENT-VOLTAGE SCAN IS DISPLAYED ON A CATHODE-RAY TUBE, GIVING RISE TO THE NAME CATHODE-RAY POLAROGRAPHY. THE POLAROGRAPHIC OXYGEN SENSOR PERMITS DETERMINATION OF OXYGEN IN ATMOSPHERIC SAMPLES, RESPIRATORY GASES, BLOOD, AND SEA WATER. COULOMETRY IS AN APPLICATION OF FARADAY'S LAW TO QUANTITATIVE ANALYTICAL ELECTROLYSIS. THE MATERIAL DETERMINED UNDERGOES ELECTROCHEMICAL REACTION IN AN ELECTROLYSIS CELL. TWO COULOMETRIC TECHNIQUES ARE AVAILABLE: ONE USES A CONSTANT OR PROGRAMMED CURRENT AND THE TIME TO COMPLETE THE REACTION IS MEASURED, AND WORKING ELECTRODE POTENTIAL IS CONTROLLED CAREFULLY, PRODUCING AN EXPONENTIALLY DECAYING CURRENT THAT IS INTEGRATED TO OBTAIN THE QUANTITY OF CURRENT IN THE SECOND TECHNIQUE. COULOMETRY PROVIDES THE BASIS FOR VERY ACCURATE CHEMICAL ANALYSES. THREE TYPES OF ION-SELECTIVE SOLID PARTICLES OF A COMPOUND, FOR EXAMPLE, SILVER IODIDE, ELECTRODES HAVE BEEN DEVELOPED: GLASS, SOLID STATE, AND LIQUID ION EXCHANGE. SOLID-STATE MEMBRANE ELECTRODES ARE OF TWO TYPES, BUT THE ESSENTIAL ELEMENT IN EACH IS A RELATIVELY INSOLUBLE COMPOUND. THE FIRST TYPE CONSISTS OF SOLID PARTICLES OF A COMPOUND, FOR EXAMPLE, SILVER IODIDE, EMBEDDED IN A MATRIX OF SILICONE RUBBER. THE SECOND TYPE CONSISTS OF AN APPROPRIATE CRYSTALLINE MATERIAL INSTEAD OF THE IMPREGNATED MEMBRANE. THE NEED FOR CALIBRATION STANDARDS HAVE INCREASED USING ELECTROCHEMICAL METHODS.

• Supplemental Notes:
  • pp 68-74, 2 FIG, 2 PHOT
• Authors:
  • Taylor, J K
• Publication Date: 1968-10

Media Info

• Serial:
  • Industrial Research
  • Publisher: Dun Donnelley Publishing Corporation

Subject/Index Terms

• TRT Terms: Calibration; Cathode ray tubes; Chemical analysis; Electrical measurement; Electrochemistry; Electrolysis; Optical instruments; Oxygen; Sensors; Volumetric analysis
• Old TRIS Terms: Cathode rays; Coulometers /volt ammeters/; Polarimeters; Polarographic analysis
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00216818
• Record Type: Publication
• Files: TRIS
• Created Date: May 19 1994 12:00AM