Xiaoqing Jiang, Fengyun Tian, Fan Yang

College of Chemistry, Liaoning University

Xuekai Dou b , Jun Wang, Youtao Song

School of Environment, Liaoning University

Graphical Abstract

Eu^III -dtpa-bis(mel) was designed and synthesized as a novel targeting fluorescence probe for melamine detection. The ligand field change around Eu^III caused by melamine leads to a highly selective fluorescence “turn-on” response. The competitive assay showed that the presence of other analogues (cyanuric acid, cyanuric 4 chloride, trichloroisocyanuric acid and acetoguanamine) rarely affected the fluorescence intensity in probing melamine. The results displayed a linear correlation beteewn melamine concentration and fluorescence intensity. The linear equation was y = 38.68x + 568.32 (R² = 0.9972) with melamine concentration ranged in 5-100 µmol/L. When melamine concentration reaches 100 µmol/L, the fluorescence intensity becomes the maximum. The formed Eu^III -dtpa-bis(mel)-melamine complex was extremly stable with the stability constant (k) of 9.90 × 10⁶ and the ratio was 1:1. The detection limit (LOD) was 0.3743 µmol/L. The recoveries ranged from 99.80 to 100.50 %, when melamine was detected in some milk products. It can be confirmed that EuIII -dtpa-bis(mel) shows high selectivity, sensitivity and recognition ability in melamine detection.

Abstract

Eu^III -dtpa-bis(melamine) was designed and synthesized as a novel targeting fluorescence probe for melamine detection in milk products. The ligand field change around Eu^III caused by melamine leads to a highly selective fluorescence “turn-on” response. The competitive assay showed that the presence of other analogues (cyanuric acid, cyanuric chloride, trichloroisocyanuric acid and acetoguanamine) rarely affected the turn-on fluorescence intensity in probing melamine. The obtained results displayed a linear correlation between melamine concentration and fluorescence intensity. The linear equation was y = 38.68x + 568.32 (R2 = 0.9972) with melamine concentration ranged from 5-100 µmol/L. When melamine concentration reaches 100 µmol/L, the fluorescence intensity becomes the maximum. The formed EuIII -dtpa-bis(melamine)-melamine complex was extremely stable with the stability constant (k) of 9.90 × 106 and the complexation ratio was 1:1. The detection limit (LOD) was 0.3743 µmol/L. The recoveries ranged from 99.80 to 100.50 %, when melamine was detected in some milk products. It can be confirmed that Eu^III -dtpa-bis(melamine) shows high selectivity, sensitivity, targeting and recognition ability in melamine detection.

Read the article here:       30-Design and synthesis of a novel lanthanide fluorescent probe (EuIII-dtpa- (bis)melamine) and application in melamine detection in milk products.pdf