Abstract: Antibodies were obtained from antisera raised in rabbits against a thaumatin-glutaraldehyde conjugate. The cited electrodes were prepared by galvanostatic electropolymerization of a solution containing 0.5 M pyrrole and 100-1000 ppm of thaumatin antibody on to a Pt substrate, using current densities of 0.25-1 mA/cm2 for 5 min. The resulting antibody-containing poly(pyrrole) electrodes were used in a flow injection system to determine thaumatin. A portion (50 µL) of thaumatin solution was injected into a carrier stream (1 ml/min) of 0.05 M phosphate buffer of pH 7.4 and transported to the antibody-containing poly(pyrrole) electrode. Pulsed amperometric detection was applied and the concentration of thaumatin present was determined by measuring the current produced. The calibration graph was linear up to 120 ppm of thaumatin.

Abstract: 7α-Carboxymethylthio-17α-hydroxyprogesterone (I), was prepared from 17α-hydroxyprogesterone (II) and condensed with 1-hydroxybenzotriazole in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodi-imide hydrochloride. The activated ester was immobilized on aminoalkyl porous glass beads in dioxan/pyridine (1:1). The IgG fraction of rabbit antiserum raised against a I-BSA conjugate was digested with mercuripapain to give Fab fragments. After condensation with fluorescein isothiocyanate, the labelled material was separated on DEAE-Sephadex A-50, with gradient elution from 0.15-1 M NaCl in 10 mM sodium phosphate buffer of pH 7.3 and then on Sephadex G-25 to give F1-Fab. The glass beads were added to the F1-Fab solution at 37°C until the fluorescence intensity at 522 nm (excitation at 495 nm) was no longer decreased. For the flow injection technique, the reactor consisted of F1-Fab bound with immobilized antigen packed in a stainless-steel column (1 cm x 4.6 mm i.d.) connected to a solvent delivery apparatus and equilibrated with 10 mM phosphate buffer of pH 7.3 at 40°C, with detection at 525 nm (excitation at 480 nm). The calibration graph was linear for 10^-300 ng of II.

Abstract: The sample (10 µL) was treated with aqueous 0.3 mM Fe(III) solution (90 µL) and acetate buffer (200 µL) and the mixture was incubated at 30°C. Proteins were pptd. by addition of aqueous 1.25 M HClO4 (200 µL). After centrifuging, the supernatant solution was analyzed by flow injection analysis with use of aqueous 0.5 M NaSCN as the detection reagent; the complex formed was monitored at 480 nm. Tests carried out on human and rabbit serum revealed the presence of a ferroxidase-like substance other than ceruloplasmin. The coefficient of variation (n = 6) was 3.4%. No interferences were observed in the presence of Zn(II), Ni(II), Cd(II), Pb(II), Ca(II), Mg(II), Cl-, PO43-, SO42-, CO32-, CO32-, ClO4-, NO2- or S2O3-, whereas Cu(II), Cr(III), N3-, NO3- and SCN- interfered.