Atomic absorption spectrometric detection of biotin-cymantrene as a metallo-tracer for the avidin–biotin system

Abstract

Biotin-cyclopentadienylmanganese tricarbonyl (biotin-cymantrene; biotin-Cy) is proposed as a universal metallo-tracer for immunoassays. Associated with the possibility of detecting this type of label (organometallic moieties) along with different analytical procedures, this reagent appears to be a universal system with the advantages of being inexpensive, stable and directly detected (no substrate is required). The optimum conditions for detecting the organometallic label biotin-Cy with a Zeeman atomic absorption spectrometer and the affinity of biotin-Cy for the streptavidin ligand immobilized on the walls of microtitre plates, wells or tubes are described. The results obtained demonstrate the possibility of assaying a wide range of clinical parameters because the detection limit of biotin-Cy is about 1 pg per assay. Based on the competition between immobilized bovine serum albumin adsorbed on the wall and free bovine serum albumin for specific polyclonal antibodies, the streptavidin-metallo-biotin system was tested on a competitive immunoassay model and a satisfactory calibration graph was obtained.