A 12-Metal Cd(II)-Eu(III) Nanocluster for Luminescence Detection of Piroxicam as an Anti-inflammatory Drug

A 12-metal Cd(II)-Eu(III) nanocluster [Cd₈Eu₄L₈(OAc)₈](SO₃CF₃)₄ 4(MeOH)·2(EtOH)·8(H₂O) (1, H₂L = 8,8'-((1E,1'E)-(((octane-1,8-diylbis(oxy))bis(2,1-phenylene))bis(azaneylylidene))bis(methaneylylidene))bis(2-ethoxyphenol)) was constructed for the luminescence detection of piroxicam (PRX). The enhancement of Eu(III) luminescence caused by PRX is described by I_615 nm = k × [PRX] + a, which can be used to determine the concentrations of PRX in fetal calf serum and the real drug with high selectivity and sensitivity. Prepared test strips of 1 are used to qualitatively check PRX through the color change to red, and real-time quantitative analysis of PRX can be further achieved through smartphone scanning. The luminescence response time of 1 toward PRX is about five seconds, while the limits of detection are from 0.13 nM to 0.58 nM (ppb level).