Abstract: An automatic analytical apparatus in which a series of operations ranging from the sampling into a treating receptacle, pretreatment, analysis and discharge of a fluid sample to the preparation for the next analysis are repeated automatically in order, wherein the time-dependent variation of the composition is traced successively. This permits the presence of the composition variation or the course of the composition variation to be confirmed or the composition variation to be controlled, automatically.

Abstract: This apparatus essentially comprises a coulometric cell (10) having an electrically insulating tight enclosure (12, 14, 30) containing a cathode (20) and an anode (22) which face one another and defining between them a space (21) for the passage of the solution to be enriched by said ions, a pipe (42) for supplying the solution to be enriched with ions and a pipe (44) for the discharge of the ion-enriched solution and issuing into said space (21), electric supply conductors (24, 26) for the cathode and the anode, the cathode and/or the anode containing said ions and being able to release them during the passage of the current and a current-stabilized electric supply source (28) connected to said conductors (24, 26).

Abstract: An amperometric method for the direct measurement of acidity in a medium which contains at least one ester of an acid containing oxygen, and whose dielectric constant is lower than 30. The method provides for maintaining a constant voltage between an ultramicroelectrode and a counterelectrode and measuring the current therebetween as an increasing quantity of diphenylphosphoric acid is added to the medium via a microburette. The measured current being indicative of the acidity of the medium under test. A predetermined curve is provided which represents the relationship between the acidity of the medium and the current measured by the system.

Abstract: A coated-wire electrode for potentiometrically titrating surfactant molecules having more than ten carbon atoms includes an electrically-conductive core coated with a semipermeable membrane. The membrane matrix included a polymer, a plasticizer and an ion-exchange material consisting essentially of dimidium bromide or disulphine blue in suitable proportions to be surfactant selective. The membrane is responsive to anionic, cationic and amphoteric surfactants as well as alkoxylated nonionic surfactants.

Abstract: A high pressure coulometric titration apparatus features a pressure vessel for containing a titration vessel, which is capable of being subjected to a pressure above the vaporization pressure of the sample to be analyzed. A back pressure regulator is employed to maintain the internal chamber created by the pressure vessel at this predetermined pressure level, so that the sample will remain in a liquid phase throughout the analysis. A fluid control arrangement is also provided for sweeping the chamber with a dry, inert gas, as well as conveying a predetermined amount of the sample to the titration vessel. This fluid control arrangement in combination with the pressure vessel operates to insure that all of the water in the sample will be trapped in the solvent, as well as to prevent the introduction of extraneous water into the system.

Abstract: Described is a process for determining the zinc content of an acid aqueous phosphating bath. A bath sample is titrated at a pH value between 1.2 and 1.7 in the presence of ethylenediaminetetraacetic acid, hexamethylenetetramine and alkalihexacyanoferrate (III) with an alkalihexacyanoferrate(II) until the potential at an oxidation-reduction electrode immersed into the bath sample reaches an inflection point.Any content of nitrite and/or iron(II) ions must be removed by an addition of nitrite-destroying substances and by an oxidation to iron(III) ions at a pH value above 8.The process is particularly suitable for determining the zinc concentration of phosphating baths which contain 0.4 to 2.0 g/l Zn. The presence in phosphating baths of additional cations such as manganese and/or calcium and/or nickel and/or magnesium does not interfere with the process. The analysis can be automatic and may directly be used to control a metering device for supplying make-up concentrates to the phosphating bath.

Abstract: A chemical process control system includes a plurality of sensors for sensing various parameters of several baths employed in a chemical process. A microprocessor is employed to interrogate each sensor, to determine bath characteristics from one or more of the parameters, and for comparing the parameters to established limits. The microprocessor initiates corrective responses whenever a characteristic falls outside its specific limits in an attempt to restore the characteristic to a specified operating target value.A hierarchy of authorization keys limits access to the apparatus depending upon the level of authority of the person seeking access. Different degrees of authority may be delegated for an apparatus operator, a supervisor and servicing personnel. The apparatus includes a local and remote communication capacity for sending messages concerning malfunctions in the apparatus and for receiving instructions from a remote location for correcting malfunctions.

Abstract: A system suitable for determining the concentration of an enzyme's substrate in a solution 21 containing a buffer comprises two ion-sensitive devices 22, 23, such as ISFETS, in contact with the solution, one of the devices 23, e.g. an ENFET, having a layer 24 containing an enzyme, the enzyme producing ions from its substrate, and the system comparing the responses of the two devices and providing a control signal to consume ions as they are generated at the ENFET, or to produce an equal concentration of ions at the other device, such that the concentrations sensed by each are equal. The signal gives an indication of the concentration of the substrate. Other ion-sensitive devices may be used. The concentration of other substances can be determined, for example a device with an enzyme's substrate can be used for detecting the concentration of an enzyme.

Abstract: A coated-wire electrode for potentiometrically titrating surfactant molecules having more than ten carbon atoms includes an electrically-conductive core coated with a semipermeable membrane. The membrane matrix includes a polymer a plasticizer and an ion-exchanger material consisting essentially of dimidium bromide-disulphine blue in suitable proportions to be surfactant selective. The membrane is responsive to anionic, cationic and amphoteric surfactants as well as alkoxylated nonionic surfactants.

Abstract: An electrolytic solution for Karl Fischer's coulometric titation and a method for measuring the water content of a sample using the same are disclosed. The electrolytic solution contains iodine or an iodide, sulfur dioxide, an amine and a solvent, wherein the amine is a pyridine derivative, imidazole or an imidazole derivative and the solvent is a mixture of (a) a polyhydric alcohol or an ether compound thereof, (b) methanol and (c) a halogenated hydrocarbon or an aromatic hydrocarbon. The measurement method achieves a high precision with reduced measurement time and is suitable for making water content measurements using a water content vaporization method.

Abstract: A method for titration flow injection analysis by introducing a multicomponent sample into a carrier stream which flows into a mixing/sensing cell and titrating with a reactant more than one component of the sample by sensing a plurality of endpoints. The apparatus of the invention includes a stirring means within the mixing/sensing cell which generates helical flow within the cell so that bubbles are not retained in the cell.

Abstract: The invention relates to an analytical method for determining the organic halogen content of a sample. The results of the present method are superior to known methods, and are independent of the physico-chemical properties of the halo-organic compounds in the sample. The method comprises subjecting a sample containing a halo-organic compound, preferably in solution in an aprotic solvent, to electrolysis, and determining the resulting halide ion concentration.

Abstract: An apparatus for electrochemical indication of the final stage of a titration analysis has a first indication electrode located in an electrochemical titration container connected by a switch to a sampling current amplifier feeding a recorder. Both the amplifier and the switch are controlled by a timing circuit which causes the switch to connect and disconnect the electrode to the amplifier. By only connecting the electrode to the amplifier for a brief time and activating the amplifier for a brief time thereafter, the instantaneous value of indication current is obtained. During the remaining time period, the indication electrode is galvanically disconnected from the amplifier and consequently, no reduction of concentration of electroactive substance in the proximity of the electrode occurs and an extremely high current response is attained.

Abstract: A method of detecting an electrode potential in a Karl Fischer moisture meter comprises the step of subtracting an electrode potential which is caused by a liquid resistance of a liquid sample from an electrode potential which is generated in an end point detecting electrode in the Karl Fischer moisture meter, to thereby obtain a true polarization potential.

Abstract: An analytical method for determining by potentiometric titration formaldehyde in an electroless copper plating bath, which comprises using a hydroxylamine salt such as hydroxylamine hydrochloride as the titrant and using a silver electrode as the indicator electrode. This method can determine free formaldehyde in low concentration which takes part in the plating reaction.

Abstract: An analyzer for natural gas to determine the existence of and concentration of wanted and unwanted sulfur compounds and odorizing agents.

Abstract: In a coulometric titration method, during a preparation step before a titration step a composition to be titrated is accumulated in an electrolyte.

Abstract: An electrochemical detector cell (10) and apparatus incorporating the cell (10) includes a first capillary (12) having an entrance (14) connected to an electrolyte source (30) and an exit (16). A second capillary (18) is connected to reactive gas source (32) and intersects the first capillary (12) at (22) to define a reaction zone (20) in the first capillary (12). A sensor electrode (24) is positioned in the first capillary (12) in the reaction zone (20). A third capillary (26) intersects the first capillary (12) within the reaction zone (20). A reference electrode (28) is positioned in the third capillary (26). The third capillary (26) is connected to a solution source (34). The electrodes (24) and (28) may be used for potentiometric measurements. A fourth capillary (38) intersects the first capillary between entrance (14) and intersection (22) of the first capillary (12) and the second capillary (18).