The disclosure concerns methods for the detection of an analyte in a sample by electro-chemiluminescence using new reagent compositions. New reagent compositions, reagent kits for measuring electrochemiluminscence (ECL) and electrochemiluminescence detection methods using the new reagent compositions are disclosed. In particular, the disclosure relates to the use of novel combinations of compounds which can be used in said measurements to provide improved assay performance.

There is provided a system and method of selectively monitoring ions in a fluid medium using a graphene sensor, the method comprising the step of adjusting an operating frequency of the graphene sensor to a particular resonant frequency for targeting resonance of specific ions in the fluid medium. In the proposed method, dispersive effect of the fluid medium is used to tune the graphene sensor to a desired frequency, thereby obtaining resonance response for specific ions in the fluid medium. Also, the monitoring of a specific ion in the fluid medium is unaffected by presence of a plurality of other ions in the said fluid medium.

An embodiment provides a method for measuring a characteristic of an aqueous sample, including: introducing the aqueous sample to a titration region and a reaction region of a measurement device, wherein the titration region comprises a pH electrode and a protonator electrode contacting a first portion of an aqueous sample, wherein the reaction region comprises a counter electrode contacting a second portion of the aqueous sample; placing an electrolyte reservoir in a state of electrical continuity with the titration region and the reaction region, wherein the electrolyte reservoir comprises a reference electrode, wherein the volume of the electrolyte reservoir comprises a large volume of an electrolyte; and determining a characteristic of the aqueous sample by measuring an electrochemical characteristic between the reference electrode and at least one of: the pH electrode and the counter electrode. Other aspects are described and claimed.

The present application proposes a method for detecting an okadaic acid based on a near-infrared photoelectric composite material, which includes the following steps: synthesizing NaYF.sub.4: Yb, Tm up-conversion nanoparticles (UCNPs) and a semiconductor material flower-like tungsten oxide (WO.sub.3) by a simple high-temperature solvothermal method; coupling the UCNPs with an okadaic acid monoclonal antibody through a classic amidation reaction to construct a competitive near-infrared photoelectrochemical immunosorbent assay (cNIR-PECIA) for okadaic acid detection. In addition, the present application employs a screen-printed carbon electrode (SPE) as the working electrode, and thus only requires a small amount of electrolytes, which is low-cost and maintenance-free.

An embodiment provides a method for digesting at least one analyte of an aqueous sample, including: introducing an aqueous sample comprising at least one analyte into a digestion device comprising one or more carbon substituted material electrodes; digesting the at least one analyte by applying an electrical potential between an anode and a cathode of the digestion device, wherein the digesting comprises a step-wise disintegration; measuring the at least one analyte of the aqueous sample from the digested material, using a measurement device selected from the group consisting of: an electrochemical device and an optical measurement device; and modifying the electrical potential based upon the measurement of the at least one analyte. Other aspects are described and claimed.

The present invention provides a composite comprising graphene, a conjugated porous organic polymer and a metalloprotein and to methods of making the composite. The invention also relates to articles (e.g. to an electrode) comprising the composite and to uses of the composite, e.g. in heterogeneous catalysis of oxygen reduction reactions, and in oxygen sensing.

An electrode comprising synthetic high-pressure high-temperature diamond material, the diamond material comprising a substitutional boron concentration of between 1×10.sup.20 and 5×10.sup.21 atoms/cm.sup.3 and a nitrogen concentration of no more than 10.sup.19 atoms/cm.sup.3. The electrode has a ΔE.sub.3/4-1/4 as measured with respect to a saturated calomel reference electrode in an aqueous solution containing 0.1 M KNO.sub.3 and 1 mM of Ru(NH.sub.3).sub.6.sup.3+ selected any of less than 70 mV, less than 68 mV, less than 66 mV, and less than 64 mV, and/or a peak to peak separation ΔE.sub.p as measured with respect to a saturated calomel reference electrode in an aqueous solution containing 0.1 M KNO.sub.3 and 1 mM of Ru(NH.sub.3).sub.6.sup.3+ selected any of less than 70 mV, less than 68 mV, less than 66 mV, and less than 64 mV.

The present invention relates to a new device for selective arsenic sensing using electrochemically reduced graphene oxide (ERGO) based reusable flexible electrode strip. Active electrode of the device was prepared by a very simple method in which the thin film of graphene oxide (GO) was reduced electrochemically at a low DC potential (0 to -1.5 V). The said device selectively detects As.sup.3+ in field water sample within a wide range of concentrations with a limit of detection of less than 25 ppb. More importantly, the selectivity of the electrode is independent of conductivity and TDS levels of measured field water samples which were collected from various parts of India. Selective detection of As.sup.3+ by ERGO was controlled by optimizing the surface electronic conductivity through structural modification of it during electroreduction process.

A composite material suitable for use in sensing and catalysis applications with conjugated polymers non-covalently bound to the carbon nanotubes. The conjugated polymers have alternating aromatic (Ar) units and bipyridine (BPy) units. Metal nanoparticles having a size that is between about 0.3 nm and about 5 nm are bound to the conjugated polymers at respective BPy units, thereby anchoring the metal nanoparticles to the carbon nanotubes. Thus, a metal salt solution was added into the polymer/carbon nanotube solution to form a metal-BPy complex, which is in situ photo reduced to metal nanoparticles. Therefore, the formed nanoparticles are tightly anchored to the nanotube and can be self-regenerated by room light to offer the material a high performance and durability.

A sensor comprising an elongate member comprising an electrochemical sensor comprising an electrochemical filament extending along the length of the elongate member, wherein the elongate member comprises a fibre formed from a drawable material.