Multifunctional dendritic molecular probes that selectively detect Cu.sup.2+ ions via potentiometric and fluorometric techniques with low detection limits are disclosed. The selective and reversible binding of the molecules with the Cu.sup.2+ ion was used to make solid-state microsensors by incorporating the molecular probes into the carbon-based membranes as an ionophore for Cu (II).

Method and system for detecting and/or quantifying Δ.sup.9-tetrahydrocannibinol (THC) in exhaled breath. In one embodiment, the method involves providing an electrochemical sensing element, the electrochemical sensing element including a working electrode, and also providing a filter that traps THC in exhaled breath. Next, a subject exhales onto the filter, whereby at least some of the THC, if present, is trapped in the filter. Next, the filter is washed with an eluent, whereby at least some of the THC trapped in the filter is eluted in an eluate. Next, the eluate is deposited onto the working electrode of the electrochemical sensing element, and the eluate is dried, whereby any THC present is immobilized on the working electrode. Next, an electrolytic solution is delivered to the electrochemical sensing element, and the THC immobilized on the working electrode is directly electrochemically detected and/or quantified using a pulse voltammetry technique, such as square-wave voltammetry.

This application features a method of forming a nanoporous layer. The method includes steps of dispensing on a substrate a colloid composition comprising a liquid and a number of nanoparticle clusters, and subjecting the dispensed colloid composition to drying to form the nanoporous layer over the substrate. The nanoporous layer includes nanoparticles deposited to form a three dimensional network of irregularly shaped bodies. The nanoporous layer also includes a three dimensional network of irregularly shaped spaces that are not occupied by the three dimensional network of irregularly shaped bodies.

A solid-state soil nutrient sensor comprising a sensor blade for inserting into the soil, the sensor blade comprising an electrically insulating substrate. The sensor may further comprise first and second electrodes disposed on the substrate, each electrode comprising: a sensing region located towards an end of the sensor blade inserted into the soil, and a contact region displaced away from the end of the sensor blade and electrically connected to the sensing region, for making an electrical connection to the electrode. The sensor may further comprise electrical insulation over each of the first and second electrodes between the sensing region and the contact region; a reference membrane over the sensing region of the first electrode; and a nutrient sensing membrane over the sensing region of the second electrode; and the reference and nutrient sensing membrane each comprise one or more layers of solvent-cast polymer.

Disclosed herein are compositions for permeable outer diffusion control membranes for creatinine and creatine sensors and methods of making such membranes.

The present disclosure includes to a sensor element including a membrane having a first functionalized region and a second functionalized region and including a sensor element body on which the membrane rests. The sensor element body has at least one electrically conductive first conductor and an electrically conductive second conductor electrically insulated from the first conductor. The first conductor is electrically and/or electrolytically conductively connected to the first functionalized region of the membrane, and the second conductor is electrically and/or electrolytically conductively connected to the second functionalized region of the membrane. In another aspect of the present disclosure, a method for fabricating such a sensor element is disclosed.

A method of and an apparatus for manufacturing a measuring cell comprising a tube having a first end capped by a membrane of an ion-selective material, comprising the steps of: providing a paste comprising all constituents of the ion-selective material; mounting the tube onto a stick with a tip such that the stick extends through the tube; dispensing an amount of the paste onto the tip; heating the first end of the tube and the dispensed paste to a temperature causing the dispensed paste to melt and the thus-produced melt to form a film covering the tip and an end surface of the first end of the tube; transforming the film into the membrane joined to the tube by cooling the first end of the tube and the film to a temperature below a melting point of the ion-selective material; and separating the thus-manufactured measuring cell from the stick.

A method of manufacturing membranes consisting essentially of an ion-selective material is disclosed. The method comprises: providing a spreadable base material; dispensing a quantity of the base material onto a top side of a tray, wherein the top side includes a set of coplanar flat surface segments, each having a surface area corresponding to a disc area of one of the membranes to be manufactured, and wherein at least the top side of the tray consists essentially of a non-adhesive material; distributing the dispensed base material across the top side of the tray such that a thickness of the distributed base material covering the coplanar surface segments corresponds to a predetermined thickness; transforming the thus-distributed base material into ion-selective material comprising one or more coplanar sheets covering the coplanar surface segments; and removing individual membranes from the tray, each defining a disc-shaped section of the ion-selective material.

This disclosure relates to a glucose-sensing electrode including a nanoporous metal layer and an electrolyte ion-blocking layer formed over the nanoporous metal layer. The nanoporous metal layer is capable of oxidizing both glucose and maltose without an enzyme specific to glucose in the glucose-sensing electrode. The electrolyte ion-blocking layer is configured to inhibit Na.sup.+, K.sup.+, Ca.sup.2+, Cl.sup.−, PO.sub.4.sup.3− and CO.sub.3.sup.2− from diffusing toward the nanoporous metal layer such that there is a substantial discontinuity of a combined concentration of Na.sup.+, K.sup.+, Ca.sup.2+, Cl.sup.−, PO.sub.4.sup.3− and CO.sub.3.sup.2− between over and below the electrolyte ion-blocking layer.

Disclosed are internal electrolyte layers for ion selective electrodes, wherein the internal electrolyte layers contain carbon paste doped with a metal salt. Also disclosed are ion selective electrodes and sensor array assemblies containing the internal electrolyte layers. Also disclosed are methods of producing and using the internal electrolyte layers, ion selective electrodes, and sensor array assemblies.