Abstract: An embodiment provides a probe, including: an ion selective shell that includes a pH electrode bathed in an electrolyte and/or buffer solution; a plurality of conductive electrodes coaxially arranged respective to the pH electrode; the plurality of conductive electrodes being electrically isolated on a substrate displaced between the pH electrode and a reference electrode, and including: at least a first conductive electrode that is exposed to sample fluid at a terminal end of the probe proximate to the ion selective shell and disposed on the surface of an electrode substrate proximate to a terminal end of the reference electrode; and at least a second conductive electrode that is exposed to the sample fluid at the terminal end of the probe proximate to the ion selective shell and disposed on the surface of an el electrode substrate proximate to the terminal end of the reference electrode; the probe further including the reference electrode arranged about and along a longitudinal axis of the probe and bathed

Abstract: An embodiment provides a method for determining the alkalinity of an aqueous sample using an alkalinity sensor, including: monitoring the pH of an aqueous sample using a pH sensor in a sample cell, the pH sensor including a pH sensor electrode made of boron-doped diamond; generating hydronium ions, using a hydronium generator, in the aqueous sample in the sample cell, the hydronium generator including a hydronium-generating electrode; changing the pH of the aqueous sample by causing the hydronium generator to generate an amount of hydronium ions in the aqueous sample; quantifying and converting a current or charge to the number of hydronium ions produced to an end point of the electrochemical titration, the end point correlating to the alkalinity of a sample; and analyzing the alkalinity of the aqueous sample based on the generated amount of hydronium ions and the resulting change in pH monitored by the pH sensor.

Abstract: An embodiment provides an amperometric sensor, including: a housing containing an inner fill solution; an electrode bathed in the inner fill solution; and a membrane in intimate contact with the electrode; the electrode being formed as a non-compact or porous structure on the membrane; whereby a spatial relationship of the electrode and the membrane is constant. Other embodiments are described and claimed.

Abstract: An embodiment provides a probe, including: an ion selective shell that includes a pH electrode bathed in an electrolyte and/or buffer solution; a plurality of conductive electrodes coaxially arranged respective to the pH electrode; the plurality of conductive electrodes being electrically isolated on a substrate displaced between the pH electrode and a reference electrode, and including: at least a first conductive electrode that is exposed to sample fluid at a terminal end of the probe proximate to the ion selective shell and disposed on the surface of an electrode substrate proximate to a terminal end of the reference electrode; and at least a second conductive electrode that is exposed to the sample fluid at the terminal end of the probe proximate to the ion selective shell and disposed on the surface of an el electrode substrate proximate to the terminal end of the reference electrode; the probe further including the reference electrode arranged about and along a longitudinal axis of the probe and bathed

Abstract: One embodiment provides a method, including: initiating, at a generator electrode in an electrode array having a collector electrode adjacent to but physically separate from the generator electrode, a reduction reaction for an oxygen containing species and a monochloramine species present in a water sample; said initiating comprising generating, at the generator electrode, a generator current producing the reduction reaction; detecting, at the collector electrode, a collector current associated with products formed from the reduction reaction; wherein the electrode array is biased to preferentially detect one or more products of the reduction reaction; and determining, by comparing the generator current with the collector current, concentrations of oxygen containing species and monochloramine species present in the water sample.

Abstract: An embodiment provides an amperometric sensor, including: a housing containing an inner fill solution; an electrode bathed in the inner fill solution; and a membrane in intimate contact with the electrode; the electrode being formed as a non-compact or porous structure on the membrane; whereby a spatial relationship of the electrode and the membrane is constant. Other embodiments are described and claimed.

Abstract: An embodiment provides a method for determining the alkalinity of an aqueous sample using an alkalinity sensor, including: monitoring the pH of an aqueous sample using a pH sensor in a sample cell, the pH sensor including a pH sensor electrode made of boron-doped diamond; generating hydronium ions, using a hydronium generator, in the aqueous sample in the sample cell, the hydronium generator including a hydronium-generating electrode; changing the pH of the aqueous sample by causing the hydronium generator to generate an amount of hydronium ions in the aqueous sample; quantifying and converting a current or charge to the number of hydronium ions produced to an end point of the electrochemical titration, the end point correlating to the alkalinity of a sample; and analyzing the alkalinity of the aqueous sample based on the generated amount of hydronium ions and the resulting change in pH monitored by the pH sensor.

Abstract: A sensor for measurement of free chlorine and of total chlorine in aqueous solution including a working electrode having a self-assembled monolayer (SAM) formed on the surface thereof, producing a barrier which reduces the generation of background currents when electrical potentials are applied to the electrode, and blocks the reduction or oxidation of interfering species in the solution, is described. Such SAMs have also been found to block the efficient reduction of chlorine as well. However, N,N-diethyl-p-phenylenediamine (DPD) has been found to effectively transport electrons across the SAM; that is, an oxidized form of DPD produced by a reaction with chlorine is capable of penetrating the SAM such that the reduction of the oxidized DPD species can occur. The generated reduction current is correlated with the concentration of chlorine in solution. Total chlorine may be determined by the addition of an iodide salt.

Abstract: A sensor for measurement of free chlorine and of total chlorine in aqueous solution including a working electrode having a self-assembled monolayer (SAM) formed on the surface thereof, producing a barrier which reduces the generation of background currents when electrical potentials are applied to the electrode, and blocks the reduction or oxidation of interfering species in the solution, is described. Such SAMs have also been found to block the efficient reduction of chlorine as well. However, N,N-diethyl-p-phenylenediamine (DPD) has been found to effectively transport electrons across the SAM; that is, an oxidized form of DPD produced by a reaction with chlorine is capable of penetrating the SAM such that the reduction of the oxidized DPD species can occur. The generated reduction current is correlated with the concentration of chlorine in solution. Total chlorine may be determined by the addition of an iodide salt.

Abstract: A method of making a sensor to measure an analyte in a solution is disclosed. The method comprises: providing a substrate, printing conductive ink on the substrate to form a plurality of electrode regions, depositing an electrical insulation to cover one of the electrode regions, sonically ablating the electrical insulation to form an array of pores through the electrical insulation to the conductive ink in the one electrode region, and depositing metal into the pores to form an array of electrodes in the one electrode region.