Amperometric separation-free immunosensor for real-time environmental monitoring

Immunoanalytical techniques have found widespread use due to the characteri stics of specificity and wide applicability for many analytes, from large p olymer antigens, to simple haptens, and even single atoms. Electrochemical sensors offer benefits of technical simplicity, speed and convenience via d irect transduction to electronic equipment. Together, these two systems off er the possibility of a convenient, ubiquitous assay technique with high se lectivity. However, they are still not widely used, mainly due to the compl exity of the associated immunoassay methodologies. A separation-free immuno analytical technique is described here, which has allowed for the analysis of atrazine in real time and in both quasi-equilibrium and stirred batch co nfigurations. It illustrated that determinations as low as 0.13 muM (28 ppb ) could be made using equilibrium incubation with an analytical range of 0. 1-10 muM. Measurements could be made between 1 and 10 mM within several min utes using a real-time, stirred batch method. This system offers the potent ial for fast, simple, cost-effective biosensors for the analysis of many su bstances of environmental, biomedical and pharmaceutical concern. (C) 2001 Elsevier Science B.V. All rights reserved.