Cadmium II is a common water pollutant with high toxicity. It is of significant importance for detecting aqueous contaminants accurately, as these contaminants are harmful to human health and environment. The influence of hydrogen overflow was decreased and the current response was enhanced because the modified graphene extended the potential range of the electrode. The calculated detection limits are 1.
In the method, reagents and kits particles can he employed; for instance, for setting upon the electrode surface by gravity, centrifugation or magnetic attraction.
The apparatus can include a magnet for generating a magnetic field in a region proximate the electrode. Reference is also made to the concurrently filed application of Massey et al.
All of the above-referenced applications are hereby incorporated herein by reference. Field of The Invention This application relates generally to methods and apparatus for conducting binding assays, more particularly to those which measure the presence of an analyte of interest by measuring luminescence emitted by one or more labeled components of the assay system.
More specifically, the invention relates to precise, reproducible, accurate homogeneous or heterogeneous specific binding assays of improved sensitivity in which the luminescent component is concentrated in the assay composition and collected on the detection system before being caused to electrochemiluminescence.
Background of The Invention Numerous methods and systems have been developed for the detection and quantitation of analytes of interest in biochemical and biological substances. Methods and systems which are capable of measuring trace amounts of microorganisms, pharmaceuticals, hormones, viruses, antibodies, nucleic acids and other proteins are of great value to researchers and clinicians.
A very substantial body of art has been developed based upon the well known binding reactions, e. The high degree of specificity in many biochemical and biological binding systems has led to many assay methods and systems of value in research and diagnostics. Typically, the existence of an analyte of interest is indicated by the presence or absence of an observable "label" attached to one or more of the binding materials.
Of particular interest are labels which can be made to luminesce through photochemical, chemical, and electrochemical means. Fluorescence and phosphorescence are types of photoluminescence.
Chemiluminescent assay techniques where a sample containing an analyte of interest is mixed with a reactant labeled with a chemiluminescent label have been developed.
The reactive mixture is incubated and some portion of the labeled reactant binds to the analyte. After incubation, the bound and unbound fractions of the mixture are separated and the concentration of the label in either or both fractions can be determined by chemiluminescent techniques.
The level of chemiluminescence determined in one or both fractions indicates the amount of analyte of interest in the biological sample. Electrochemiluminescent ECL assay techniques are an improvement on chemiluminescent techniques. They provide a sensitive and precise measurement of the presence and concentration of an analyte of interest.
In such techniques, the incubated sample is exposed to a voltammetric working electrode in order to trigger luminescence.
In the proper chemical environment, such electrochemiluminescence is triggered by a voltage impressed on the working electrode at a particular time and in a particular manner. The light produced by the label is measured and indicates the presence or quantity of the analyte.
The disclosures of the aforesaid applications are incorporated by reference. It is desirable to carry out electrochemiluminescent assays without the need for a separation step during the assay procedure and to maximize the signal modulation at different concentrations of analyte so that precise and sensitive measurements can be made.
Among prior art methods for nonseparation assays are those which employ microparticulate matter suspended in the assay sample to bind one or more of the binding components of the assay.
The methods disclosed involve binding the antigen or antibody to latex particles which perform the function of light scattering or adsorption. The shell contains functional groups to which compounds of biological interest can be covalently bonded, and the high refractive index of the core results in high sensitivity to light scattering measurements.
Based upon this prior art, it would not have appeared possible to use microparticulate matter in assays wherein a luminescent phenomenon is measured. One would expect that the luminescence from free chemiluminescent or electrochemiluminescent moieties would be absorbed, scattered, or otherwise suffer interference from the microparticulate matter.
Contrary to that expectation, U. The assays may be performed in a heterogeneous one or more separation steps assay format and may be used most advantageously in a homogeneous nonseparation assay format.
In another aspect, it is directed to a system for detecting or quantitating an analyte of interest in a sample, which system is capable of conducting the assay methods using the assay compositions of the inventions. The system includes means for inducing the label compound in the assay medium to luminesce, and means for measuring the luminescence to detect the presence of the analyte of interest in the sample.
It was found that the binding of that component of the assay system to which an electrochemiluminescent moiety has been linked, to suspended microparticulate matter, greatly modulates the intensity of the luminescent signal generated by the electrochemiluminescent moiety linked to that component, thereby providing a means of monitoring the specific binding reaction of the assay system.
Even more surprisingly, the suspended particles were found to have little or no effect on the intensity of the luminescent signal generated by the electrochemiluminescent moiety linked to the component of the system which remains unbound to the suspended microparticulate matter.
Those same methods may be used to quantify the amount of analyte in a sample by comparing the luminescence of the assay composition to the luminescence of a composition containing a known amount of analyte.select article Optimization of a new polymeric chromium (III) membrane electrode based on methyl violet by using experimental design Research article Full text access Optimization of a new polymeric chromium (III) membrane electrode based on methyl violet by using experimental design.
Analysis of honey for trace elements content is necessary in food quality control(12). The climate and rich vegetation in Turkey provide a very suitable environment for apiculture which is in a state of expansion.
"An Automatic Voltammetric Analyzer for the Simultaneous Determination of Toxic Trace Metals in Wa-ter." Fresenius Z.
Anal. Chem. (Ger.), , (). Zirino, A., "Voltammetry of . The invention relates to methods, apparatus, reagents, and kits for performing a binding essay for an analyte of interest present in a sample based upon electrochemiluminescence at an electrode of interest.
In the method, reagents and kits particles can be employed; for instance, for setting upon the electrode surface by gravity, centrifugation or magnetic attraction. The study was aimed at developing suitable chromatographic conditions and pretreatment methods for reliable trace analysis of cyanide in drinking water and seawater.
Water Res., 19, 7 (). 82 Goncalves, M., et al., "Voltammetric methods for distinguishing between dissolved and particulate metal ion concentrations in the presence of hydrous oxides. A .