Sensitive Terbium Probes for Luminescent Determination of both Alkaline Phosphatase and Codeine Phosphate

摘要

New terbium complexes of 2-oxo-4-hydroxy-quinoline-3-carboxylic acid derivatives are reportedfor determination of alkaline phosphatase (aPase) and codeine phosphate (CP). Complexa-tion with terbium occurs by way of the oxygen atoms of the 4-hydroxyl group and the car-bonyl group of the 3-carboxy function, respectively. The complexes are highly luminescent anddo not require luminescence enhancers. The excitation maxima of the terbium chelates areat 320 nm. The assay is based on the quenching of the hypersensitive 545-nm luminescenceof the terbium complexes with the ligands 4-hydroxy- 1-methy1-2-oxo-1,2-dihydro-quinoline-3-carboxylic acid (5-ethyl-[1,3,4]thiadiazol-2-yl)-amide (L1) and 1-ethy1-4-hydroxy-2-oxo-1,2-dihydro-quinoline-3-carboxylic acid (4-trifluoromethyl-phenyl)-anode (L2) by phosphate ions.The assays require equimolar (1.0 μM) concentrations of Tb~(3+)and of the ligand at pH 8.0 (Tris-HC1 buffer). The luminescence quenching is proportional to the concentration of aPase and CPwithin the range of 0.1-70 mU mL~(-1) and 0.3-20 μg mL~(-1), respectively. The detection limits were0.05 mU mL~(-1) 40.0 pmolL~(-of aPase and 0.120μg mL~(-CP.