Quantitative detection of luteolin and quercetin in natural samples with the composite of reduced graphene oxide and cyclotriveratrylene-based metal-organic framework

Design and construction of high-efficiency electrochemical sensors for luteolin (LU) and quercetin (QCT) are greatly necessary for the detection of their excessive intake. In this work, a new metal-organic framework (MOF), [Zn2L(OH-bdc)2].2.5 H2O (1), was assembled with cyclotriveratrylene ligand (L), Zn(II) cation and 5-hydroxyisophthalic acid (OH-H2bdc). 1 featured a two-dimensional (2D) network structure. To improve the conductibility of 1, typical carbon materials, such as multi-walled carbon nanotube (MWCNT), mesoporous carbon (MC) and reduced graphene oxide (RGO) were respectively combined with the sample of 1. Markedly, synergistic effects between 1 and RGO enabled the 1@RGO(1:2) composite to exhibit efficient electrocatalytic performances for LU and QCT detection. Under the optimal condition, 1@RGO(1:2)/GCE featured the relatively wide linear range (0.02-14 mu M for LU and 0.02-14 mu M for QCT) and low limits of determination (LODs) (0.0022 mu M for LU and 0.0049 mu M for QCT). Remarkably, 1@RGO(1:2)/GCE showed good reproducibility, acceptable stability and satisfactory anti-interference. Importantly, the sensor was applied to detect LU and QCT in the natural samples with acceptable recoveries.