Various 4-alkoxypyridine-2, 6-dicarboxylic acids were synthesized starting from 2, 6- lutidine. Through aldol condensation and Michael addition, various 4-arylpyridine-2, 6-dicarboxylic acids were synthesized starting from aromatic aldehydes and 2-acetylfuran.

Five polyaminopolycarboxylic acids (EDTA and DTPA derivatives), DTPA . pAS, DTPA . 2pAS, DTPA . pAB, EDTA . pAS and EDTA pAB, where pAS and pAB represent p-aminosalicylate and p-aminobenzoate groups, respectively, were synthesized, and the stability constants of Tb3+ complexes with these ligands were determined, for the first time, by means of pH potentiometric titration. The complexation rates of Tb(III) with these ligands were found to be very slow, so batch technique was employed in the titration. The stepwise protonation constants of the lig ands and the stability constants of their Tb3+ complexes were calculated with the program BEST. It was shown that introducing p-aminosalicylate or p-aminobenzoate groups into EDTA or DTPA. leads to the decrease in acidity. The species distributions in the complex solutions at various pH accorded with the results of fluorescence measurements. A replacement of EDTA with DTPA . 2pAS in EDTA-Tb complex solution led to the enhancement in Tb3+ sensitized luminescence. The effects of the ligands' structure on the stability and fluorescence of the complexes were discussed.

, etc. We describe here a solid-phase, competitiveTRFIA for angiotensin Ⅱ（AⅡ）. AⅡ is an eight-peptide. It plays an important role in

DTPA-pAS, EDTA-pAS, DTPA-pAB and EDTA-pAB are synthesized and confirmed by elemental analysis, IR spectra, 1H NMR and mass spectra. Fluorescent properties are investigated by mixing the four chelants with EuIIIor TbIII chloride in aqueous solution. The fluorescence intensity varies with the chelants, pH value and concentration. Only DTPA-pAS and EDTA-pAS enhance the TbIII luminescence efficiently and the fluorescence intensity varied slightly at pH 6.0–12.0. The fluorescence of TbIII-DTPA-pAS can be detected even at a concentration of 10−7 mol l−1. TbIII-DTPA-pAS has been used as a label in fluoroimmunoassay for the determination of human serum albumin (HSA).