Metal–Organic Framework Loaded by Rhodamine B As a Novel Chemiluminescence System for the Paper-Based Analytical Devices and Its Application for Total Phenolic Content Determination in Food Samples

Herein, a novel paper-based chemiluminescence (CL) device has been reported for the estimation of total phenolic content of food samples. The CL system implemented on the paper was based on hydrogen peroxide (H2O2)-rhodamine b (RhoB)-cobalt metal organic framework (CoMOF) reaction. It was found that the reaction of H2O2 with RhoB molecules, loaded into the nano-pores of CoMOF (R@CoMOF), can produce an intensive CL emission. The experiments on the paper indicated that in the presence of CoMOF, the CL emission was greatly increased. In addition to this strong catalyzing effect, application of CoMOF on the paper improved the stability of CL system for several days. As a useful analytical application for the ob-tained paper-based CL device (PCD), it was examined for the detection of phenolic antioxidants. It was observed that the addition of 5 µL of phenolic compounds (PC) on the paper containing the CL reagents can remarkably decrease the CL in-tensity. This effect was applied to design a simple analytical assay for PC. After optimization process, the best sensitivity was obtained for gallic acid, quercetin, catechin, kaempferol and caffeic acid with detection limits of 0.98, 1.36, 1.48, 1.81 and 2.55 ng mL-1, respectively. The relative standard deviations (RSD%) were also less than 5%. This study is the first re-port on the practical application of PCD using a nanomaterial assisted CL reaction. It is simple, portable, low-cost and con-sumes a very low amounts of reagents and sample solution. The device was successfully applied for the investigation of total antioxidant capacity of molasses and honey samples.