Abstract: Provided are a method and apparatus for measuring free residual chlorine concentration that is accurate and simple, which can obtain objective measurement results without using any harmful reagents, and without being affected by the potential window.

Abstract: An ozone water concentration measurement apparatus that is capable of measuring ozone concentrations with high accuracy and without using an electrolyte brings at least a counter electrode and a working electrode into contact with ozone water, which is a sample solution (S), applies voltage between the counter electrode and the working electrode, and measures the current value at that voltage, to thereby calculate the ozone concentration in the ozone water. In the ozone water concentration measurement apparatus, the working electrode is a conductive diamond electrode, and the surface area that contacts the ozone water of the working electrode is within the range of 628 to 392,500 ?m2.

Abstract: An ozone water concentration measurement apparatus that is capable of measuring ozone concentrations with high accuracy and without using an electrolyte brings at least a counter electrode and a working electrode into contact with ozone water, which is a sample solution (S), applies voltage between the counter electrode and the working electrode, and measures the current value at that voltage, to thereby calculate the ozone concentration in the ozone water. In the ozone water concentration measurement apparatus, the working electrode is a conductive diamond electrode, and the surface area that contacts the ozone water of the working electrode is within the range of 628 to 392,500 ?m2.

Abstract: This invention provides an electrochemical analysis method for accurately detecting a harmful substance such as arsenic contained in a solution. In the electrochemical analysis method, a working electrode and a counter electrode are disposed in an object electrolytic solution. A negative potential is applied to the working electrode to electrodeposit the electrolyte onto the surface of the working electrode and thus to form an electrodeposit. Next, the potential of the working electrode is sweeped in a positive potential direction to allow the electrodeposit to elute into the solution and, at the same time, to detect a current change upon a potential change and thus to analyze an object substance dissolved as an electrolyte in the object electrolytic solution. A boron-doped electroconductive diamond electrode or an electrode with gold deposited on its surface is used as the working electrode.

Abstract: This invention provides an electrochemical analysis method for accurately detecting a harmful substance such as arsenic contained in a solution. In the electrochemical analysis method, a working electrode and a counter electrode are disposed in an object electrolytic solution. A negative potential is applied to the working electrode to electrodeposit the electrolyte onto the surface of the working electrode and thus to form an electrodeposit. Next, the potential of the working electrode is sweeped in a positive potential direction to allow the electrodeposit to elute into the solution and, at the same time, to detect a current change upon a potential change and thus to analyze an object substance dissolved as an electrolyte in the object electrolytic solution. A boron-doped electroconductive diamond electrode or an electrode with gold deposited on its surface is used as the working electrode.

Abstract: The present claimed invention is to provide a method for measuring a protein that enables to detect the protein with high accuracy and high sensitivity through an electrochemical method at a high speed with a simple operation using a simple device. With the method, a working electrode 5 and a counter electrode 4 are made to contact with a sample solution 1 containing the protein as being an object to be measured, and a voltage is impressed between the working electrode 5 and the counter electrode 4 so that a current value at the voltage can be measured and the protein can be electrochemically analyzed.

Abstract: A residual chlorine measuring method includes the steps of bringing a counter electrode, a working electrode and a reference electrode into contact with a sample solution containing a residual chlorine. Applying a voltage between the counter electrode and the working electrode and measuring a current value to calculate a concentration of the residual chlorine. The working electrode is an electrically conductive diamond electrode to which an element selected from a group of boron, nitrogen and phosphorus is doped into a diamond coating. The reference electrode is a silver/silver chloride electrode. A current value, when setting the potential of the electrically conductive diamond electrode to the silver/silver chloride electrode, is in the range of +0.5 V to +1.5 V for measurements.