Abstract: A fluoride-sensitive electrode having a tubular electrode shaft, a lanthanum fluoride crystal, which closes the end of the electrode shaft, an internal electrolyte sealed between the lanthanum fluoride crystal and a closure in the electrode shaft, and a contact wire which dips into the internal electrolyte, wherein the internal electrolyte has a pH of ?9.0 and a fluoride concentration of ?0.1 M. The invention also includes the method of using the electrode to determine fluoride ion concentration.

Abstract: The present invention concerns a sensor for voltammetric or amperometric measurement of the chlorite concentration (ClO2?) in an solution. In order to provide a chlorite sensor which permits direct measurement of the chlorite concentration without taking samples, separating off accompanying substances or adding chemicals, and which has negligible cross-sensitivity in relation to typical accompanying substances of the chlorite, such as in particular chlorine dioxide (ClO2), chlorate (ClO3?) and hypochlorite (OCl?), it is proposed in accordance with the invention that the sensor has a working electrode of gold.

Abstract: A fluoride-sensitive electrode having a tubular electrode shaft, a lanthanum fluoride crystal, which closes the end of the electrode shaft, an internal electrolyte sealed between the lanthanum fluoride crystal and a closure in the electrode shaft, and a contact wire which dips into the internal electrolyte, wherein the internal electrolyte has a pH of ≧9.0 and a fluoride concentration of ≧0.1 M. The invention also includes the method of using the electrode to determine fluoride ion concentration.

Abstract: An amperometric dual-electrode sensor having an operating electrode inside a passivable metal electrode used as the counter electrode is provided by the invention. A method for measuring the concentration of a compound or ions in a sample is also provided by this invention. In particular, a method of measuring hydrogen peroxide in a sample is described.

Abstract: It is an of this invention to provide an electrochemical measurement cell capable of measuring the concentration of gaseous and charged or neutral compounds in a liquid. Accordingly, the present invention consists in one aspect in an electrochemical measurement cell having a working and a counter electrode surrounded by an electrolyte space filled with an electrolyte with a high viscosity, wherein the electrolyte space is at least partly delimited by a hydrophilic membrane. It has been surprisingly discovered by the present invention that charged or neutral compounds in a liquid, as well as gases, can be determined by means of an electrochemical measurement cell having a hydrophilic membrane and an electrolyte with a high viscosity.

Abstract: A method is described for definition of peracids in the presence of hydrogen-peroxide in a solution with the following steps:(1) introducing an electrode-design, which provides at least one measurement electrode and one counter electrode into the solution,(2) Loading of the electrodes with varying potentials; and(3) Measurement of the current by using a measurement electrode.With such a method the peracid solutions always contain hydrogen-peroxide, which also shows similar reactions.In order to determine the peracid concentration, a value of the determined current is compared with a corresponding value of an earlier recorded electrode-design.