A self-vibrating pH probe comprise a housing containing an electronic assembly to which is coupled a vibration source element so that at least a portion of vibrations caused by the vibration source element propagate to the electronic assembly, the vibration source element being controllable for at least on/off operation. The self-vibrating pH probe further comprising a pH probe member having a probe tip at a first end, the probe member extending from the housing and mechanically and electrically coupled by a second end to the electronic assembly so that at least a portion of vibrations propagating to the electronic assembly further propagate to the probe tip; and further including a processor coupled to the electronic assembly for coordinating operation of the vibration source element and operation of the pH probe member.

According to at least one aspect of the present disclosure, a method includes applying an alternating current having a frequency at a selected voltage to a sensor, wherein the voltage is applied between a reference electrode and a working electrode of the sensor, varying the frequency of the alternating current between a lower frequency and an upper frequency, measuring an impedance of the sensor between the reference electrode and the working electrode as a function of the frequency of the alternating current, analyzing the measured impedance to determine a total impedance of the sensor and the real and imaginary components of the total impedance at each applied frequency of the alternating current, and characterizing the sensor based on the total impedance at the low frequency end of the sensor and on the real and imaginary components of the total impedances.

A probe chamber that includes a holder having a bore capable of holding a sensor or probe; a chamber housing having a central bore in fluid communication with the bore of the holder, wherein the chamber housing can be joined with the holder; and a measurement chamber in fluid communication with the central bore, wherein the measurement chamber comprises a gate, an inlet and an outlet and is capable of receiving a probe tip or sensor tip. Methods for calibrating a probe or sensor are also disclosed.

A measuring apparatus, includes: a first and a second ion-sensitive semiconductor elements and a reference electrode disposed so as to contact a medium of which a characteristic value is to be measured; a signal input unit receiving a first and a second signals from the first and the second ion-sensitive semiconductor elements, and generating a sensor signal; a processor processing the sensor signal; and a memory storing first data relating to fluctuations over time of the first and the second ion-sensitive semiconductor elements, and connected to the processor, wherein: the processor processes the sensor signal by using the first data and a cumulative energization time of the first and the second ion-sensitive semiconductor elements, and generate an output signal for the characteristic value, the first ion-sensitive semiconductor element includes a first sensitive film, the second ion-sensitive semiconductor element includes a second sensitive film different from the first material.

An embodiment provides a method for compensating for inteferants in measurement of alkalinity in a reagent-less system, including: introducing an aqueous sample into a measurement device comprising one or more series of electrodes; applying an electrical signal to the aqueous sample using the one or more series of electrodes, wherein the electrical signal is selected from the group consisting of: current and voltage; identifying, during application of the electrical signal, that the electrical signal reaches an oxidation threshold and measuring, prior to reaching the oxidation threshold, a first electrical response to the electrical signal, the first electrical response attributable to interferants in the aqueous sample; identifying, during application of the electrical signal, that the electrical signal reaches an endpoint and measuring, from the oxidation threshold to the endpoint, a second electrical response to the electrical signal; and measuring an alkalinity of the aqueous sample based upon a difference between the first electrical response and the second electrical response. Other aspects are described and claimed.

The disclosure relates to systems and methods for detecting and correcting errors in pH meter calibration or function when changing the pH of a sample, comprising measuring an initial pH, adding two or more amounts of titrant and measuring corresponding pH values, and applying a model to determine if the measured pH values correspond to pH values predicted by the model. The systems and methods can be used to control pH during viral inactivation of protein samples.

The disclosure relates to systems and methods for controlling the pH of a sample, comprising measuring an initial pH, adding an amount of titrant and measuring a second pH, and using non-dimensional modeling to normalize titrant and determine the amount of titrant needed to reach a final pH. The systems and methods can be used to control pH during viral inactivation or titration of protein samples.

Methods for in situ measurement of an oxidation reduction potential (ORP) and pH of a solution comprising iron are provided. The methods comprise measuring a kinetic parameter at an electrode surface of an electrode system comprising a working electrode, a counter electrode and a pseudo-reference electrode, wherein the kinetic parameter is associated with ferric reduction or both ferric reduction and ferrous oxidation and comparing the kinetic parameter to calibration data for the electrode system to determine the ORP and pH of the solution. Also provided are apparatus and systems for in situ measurement of an ORP and pH of a solution comprising iron. The apparatus and systems comprise an electrode system comprising a working electrode, a counter electrode and a pseudo-reference electrode and a detector for measuring a kinetic parameter at an electrode surface of the electrode system.

A calibration liquid (1) is used for calibrating a water quality measurement device (100). The water quality measurement device (100) includes a plurality of sensors to be brought into contact with a measurement target liquid so as to measure concentrations of a plurality of types of target components contained in the measurement target liquid, and measures the concentrations of the plurality of types of target components. The calibration liquid (1) includes a solution which contains the plurality of types of target components at respective concentrations determined for the target components, and the solution has a pH within a predetermined pH range.

The present disclosure relates to a method for determining at least one process variable of a medium. The method includes steps of recording a first value for the process variable by means of a first method for determining the process variable and recording a second value for the process variable by means of a second method for determining the process variable. The method also includes steps of selecting at least one of the detected values for the process variable by means of a classifier and outputting the selected value for the process variable. The present disclosure further relates to a computer program designed for executing a method according to the present disclosure, and to a computer program product having a computer program according to the present disclosure.