Ekins' ambient analyte theory predicts, counterintuitively, that an immunoassay's limit of detection can be improved by reducing the amount of capture antibody. In addition, it also anticipates that results should be insensitive to the volume of sample as well as the amount of capture antibody added. The objective of this study was to empirically validate all of the performance characteristics ...

The design of a supramolecular allosteric catalyst system for catalytic signal amplification and detection is presented. The catalyst was switched "on" by the introduction of an analyte that also behaves as an allosteric activator. Concentrations of Cl- ions as low as 800 nM were catalytically amplified and detected. The signal was transduced via a pH-sensitive fluorescent probe and observed vi...

The concept of a competitive enzyme immunoassay that utilizes simultaneously the bound and the free analyte-enzyme conjugate (heterobifunctional conjugate) for signal generation in response to varying analyte concentrations in samples has been investigated. Two antigenic sites of the heterobifunctional conjugate are used in the assay for binding to immunoglobulins: the analyte derivative binds ...

Univariate calibration method is a simple, cheap and easy to use procedure in analytical chemistry. A univariate analysis will be successful if a selective signal can be found for the analyte(s). In this work, two simple ways were used to find the selective signals, spectral ratio plot (SRP) and loading plot (LP). Both of them were able to discover the selective regions in the recorded data set...

Electrochemical sensor signal output, when recorded as a current, is primarily related to the target analyte concentration, but often also additional experimental or control parameters. When employing photo-active semiconductor electrodes, light intensity offers an parameter for sensors and opportunities new reaction/detection amplification pathways. Light stimulation can (i) excite charge carr...

EXTENDED ABSTRACT Biosensors provide a sensitive, specific, rapid, portable, and inexpensive means to fulfill the need for rapid on-site determinations of hazardous pollutants (e.g., explosives). Recent advances in instrumentation at NRL have led to two methods for measuring TNT and RDX: the FAST 2000 and the Analyte 2000. Engineering and design of both instruments was performed by Research Int...

To overcome the time and space constraints in disease diagnosis via the biosensing approach, we developed a new signal-transducing strategy that can be applied to colorimetric optical biosensors. Our study is focused on implementation of a signal transduction technology that can directly translate the color intensity signals-that require complicated optical equipment for the analysis-into signa...

In an attempt to optimize immunosensors operating with an immobilized antibody as binding protein and an analyte-enzyme conjugate as signal generator that is signitlcantly larger in molecular size than the analyte, in a previous communication (Part I) (S.-H. Paek and W. Schramm (1991) Anal. Biochem. 196) we developed mathematical models for the prediction of performance characteristics. These m...

This paper deals with the dynamic modeling, analysis, 4 and statistical signal processing of the ion channel switch biosen5 sor. The electrical dynamics are described by a second-order linear 6 system. The chemical kinetics of the biosensor response to analyte 7 concentration in the reaction-rate-limited regime are modeled by 8 a two-timescale nonlinear system of differential equations. Also, 9...

The United States Environmental Protection Agency (EPA) requires the determination of important trace elements in a variety of environmental samples. Graphite furnace atomic absorption methods are recommended for some elements including As, Se, Cd, Pb, Tl, Sb, Ag, Be and Cr. Graphite furnace analyses can be difficult due to chemical and spectral interferences. Quantification in atomic absorptio...