Novel europium-tetracycline probe for phosphate determination in microtiter plate

A new luminescent europium probe is presented for the determination of phosphate (P) in microtiter plate format. The assay is based on the quenching of the luminescence of the europium-tetracycline 1:1 complex by phosphate using a reagent concentration of 20.8 μmol/L. The probe is excited at 400 nm and displays large Stokes' shift of 210 nm. The emission maximum is located at 616 nm. The system works best at neutral pH 7. The linear range of the calibration plot is from 5•10-6 mol/L to 7.5•10-4 mol/L of phosphate, and the limit of detection is 5μmol/L.