The synthesis of a novel fluoroionophore, 5-p-[[4-(10',-15',20'-triphenyl-5'-porphinato) phenyloxyl]-1-butyloxyl]-phenyl-10,15,20-triphenylporphine (DTPP), and its application for preparation of a Hg(II)-sensitive optical fiber chemical sensor are described. The response of the sensor is based on the fluorescence quenching of DTPP by coordination with Hg(II). The porphyrin dimer-based sensor shows a linear response toward Hg(II) in the concentration range 5.2

A renewable amperometric immunosensor has been proposed for the determination of Schistosoma japonium antibody (SjAb) in rabbit serum. A paraffingraphite-Schistosoma japonium antigen (SjAg) biocomposite, which needs no additional curing, was directly used to construct the immunosensors. The analytical sample containing the desired SjAb was mixed with SjAb labeled with horseradish peroxidase (HRP) to form the incubation solution for the competitive binding assay. Amperometry was used to determine the amount of HRP fixed on the sensor surface, which was related to the content of desired SjAb. Assay conditions were optimized, including the selection of substrate, the loading of SjAg in the biocomposite, the amount of labeled SjAb in the incubation solution, the incubation time, and the temperature. Using o-aminophenol (o-AP) as a substrate, amperometric detection at-200 mV (vs SCE) resulted in a pseudolinear detection range of about 0.36 to 14μg/mL, with a detection limit of 0.36 μg/mL. Rabbit serum samples with varying infection degrees were analyzed, and the results demonstrated that the concentration that is detectable in this system meets the demands of clinical analyses. A new surface on the immunosensor for use in another competitive assay can be obtained by removing the original one and polishing the surface.

Anew phosphate ion-sensitive electrode based on a cobalt matrix has been prepared. The electrode showed a relalively selective potentiometric response toward H2PO4-which seems to originate from the COO layer covering the electrode surface. The response mechanism of the electrode is discussed in terms of the host-guest chemistry of a nonstoichiometric compound of COO.

The anion-sensitive membrane electrodes based on lipophilic metalloporphyrin derivatives (FeTPP)20 show similar anti-Hofmeister selectivity sequence: SCN->I->C104->N02->Br>C1->NOj-. The electrode with an optimum membrane composition has a linear response for SCN-between and 10-l mol/L, with a slope of 53.0 mV/pSCN-(25℃). The origin of the anti-Hofmeister response haracteristics has been discussed in view of the coordination chemistry of the metalloporphyrins. The interaction mechanism between (FeTPP)zO and SCN-is studied by UV/vis and IR spectroscopy. The transfer process of SCN-across the membrane interface is investigated by ac impedance measurements.

A new solvent polymeric membrane electrode based on Schiff base complexes of Co(II) is described which demonstrates excellent selectivity toward the iodide ion. The resulting electrode exhibits fairly low detection limits and good selectivity properties. The selectivity sequence observed is iodide>thiocyanate～nitrite>perchlorate～bromide>nitrate>chloride>sulfate. The excellent selectivity for iodide is related to the unique interaction between the central Co(II) ion and iodide. The response mechanism of the electrode was also studied with the ac impedance and spectroscopic techniques.