DEVELOPMENT OF AN AMPEROMETRIC IMMUNOSENSOR BASED ON FLOW-INJECTION ANALYSIS FOR THE DETECTION OF RED-BLOOD-CELLS

An amperometric immunosensor, based on a non-competitive sandwich assa y and flow injection analysis (FIA), was developed for the detection o f human red blood cells (RBCs). A dual working electrode, on which spe cific IgM and non-specific IgM were chemically immobilised to form sen sing and blank electrodes, respectively, was employed to determine the binding of specific blood cells and non-specific adsorption in one de termination. Horseradish peroxidase (HRP)-labelled anti-blood group A IgM was used in the assay, Sensor preparation involved chemical immobi lisation of the IgMs on glassy carbon electrodes using 1-ethyl-3(3-dim ethyl aminopropyl)carbodiimide (EDC) as a coupling reagent in the pres ence of N-hydroxysuccinimide (NHS). The interference contributions, su ch as the non-specific adsorption of the enzyme conjugate and the bloo d cells, were determined and removed. A quantitative relationship betw een the cell binding response and its concentration was obtained in th e region 1-30 x 10(8) cells ml(-1).