Chemiluminescence Catalyzed By Sepiolite Nanomaterial And Its Analytical Application

Because of the attracting features such as high sensitivity, simple and inexpensive instrumentation, rapid analysis and low background signals, chemiluminescence (CL) is of particular interest in the recent decades. Given the slow reaction rate and weak luminescence, hunting for novel and effective catalysts to enhance the CL intensity has been an attractive topic of intensive research. Sepiolite, which is environmentally friendly, has been widely used as effective catalysts, absorbent and functional materials as a result of the specificity of porosity and fibrous morphology. However, as far as we know, no article to date has yet reported the CL properties of sepiolite.In this work, we chose the luminol-H2O2 CL reaction as a model system and explored the effects of commercially available natural sepiolite on luminol CL for the first time. It was found that sepiolite possessed excellent catalytic activity on luminol-H2O2 CL system. The possible CL enhancement mechanism was proposed according to a variety of characterization methods. Moreover, satisfactory results were obtained when the proposed method was applied in the detection of H2O2 and glucose in environmental and food samples. In view of the advantages of abundant storage, low cost, and non-toxicity etc., sepiolite seems to be a promising catalyst for luminol-based CL. This work is not only of importance for expanding the application fields of sepiolite, but also for developing natural clay minerals as a new type of catalyzer for CL systems. The main contributions of this paper are as follows:1. In this section, we found sepiolite could significantly enhance the lumnol-H2O2 CL system. Based on the scanning electron microscope images (SEM), powder X-ray diffraction (XRD) and CL spectra, a possible CL mechanism was proposed.2. Based on the enhancement of sepiolite on luminol-H2O2 CL, sepiolite was used for luminol-driven CL detection of H2O2. Under the optimum conditions, the CL intensity was proportional to the concentration of H2O2 in the range from 0.01 to 8 μmol·L-1. The detection limit (S/N= 3) was 8.8 nmol·L-1 and the relative standard deviation (RSD) for twelve repeated measurements of 1.0 μmol·L-1 H2O2 was 2.5%. This proposed method had been successfully applied to detect H2O2 in tap and rain water samples with recoveries of 98-104%, which could be used as a sensitive detection tool for H2O2 analysis.3. A novel CL sensor for glucose was developed based on the enhancement of sepiolite on luminol-H2O2 CL. It was found that the CL intensity was linear with glucose concentration in the range of 7.5×10-6 to 2.0×10-3 mol·L-1, and the detection limit for glucose (S/N=3) is 3.2×10-6 mol·L-1. This proposed method has been successfully applied to detect glucose in beverage samples with good accuracy and precision.