Composite Eu-MOF@CQDs“off&on”ratiometric luminescent probe for highly sensitive chiral detection of l-lysine and 2-methoxybenzaldehyde

The high amount of l-lysine can increase the potential risk of cardiovascular disease.Additionally,2-methoxy benzaldehyde(2-MB)has high toxicity and can easily pollute the environment.In this work,carbon quantum dots(CQDs)can be encapsulated into Eu-BTB(H_(3)BTB=1,3,5-tri(4-carboxyphenyl)benzene),forming the multi-emission composite material Eu-BTB@CQDs.It has two emissions peaks(617 nm for Eu and 470 nm for CQDs).Eu-BTB@CQDs can be applied as bi-functional ratiometric“off&on”luminescent sensor for l-lysine and 2-MB with high sensitivity and selectivity,the low limit of detection(LOD)for l-lysine is 3.68μmol/L and for 2-MB is 0.54μmol/L,respectively.Additionally,Eu-BTB@CQDs can quantitatively discriminate l-lysine in the mixed d-and l-lysine water solutions(five different concentrations ratio of l/d-lysine has been set)makes the chiral detection of l-lysine are more meaningful.On the other hand,Eu-BTB@CQDs also can detect 2-MB over 4-methoxybenzaldehyde(4-MB)with high selectivity.Further the detection of 2-MB and l-lysine in the lake water real samples with the reasonable recovery rate.Finally,the detection mechanisms for l-lysine and 2-MB were also investigated and discussed in detail.