Layered Double Hydroxides Nanomaterials Catalyzed Chemiluminescence System And Its Analytical Application

Chemiluminescence (CL) has attracted considerable attention as a versatile and highly sensitive detection tool within diverse fields such as biotechnology and analytical technology. The intensity of most of CL systems is rather weak. Efficient CL signals were obtained in the presence of a suitable catalyst such as metal ions, metal complexes or expensive peroxidases. However, metal catalysts are environmentally unfriendly. Moreover, many enzymes are expensive and unstable in solution. Therefore, it is an attractive research area to develop a green catalyst for CL reaction. Layered double hydroxides (LDHs), which are environmentally friendly, have been widely used as effective catalysts, absorbent, optical materials as a result of the specificity of their lamellar structure. However, there are seldom reports on LDHs CL system. Therefore, the bridge between LDHs materials and molecular CL spectroscopy urge interdisciplinary researchers to further investigate the influence of a variety of interlayer anions in LDHs on CL. Herein, we study the effect of LDH nanomaterials on CL system, especially for the mechanism of the CL reaction. Combined with flow injection and sample pretreatment technology, these proposed methods have been successfully applied in environmental/biological field. The main contributions of this paper are as follows:1. In this section, we found Mg-Al-CO3LDHs could significantly enhance the lumnol-H2O2CL system. Based on the CL spectra, powder X-ray diffraction (XRD), scanning electron microscope images (SEM), and carbonate loading experiment, a possible CL mechanism was proposed. This work has exploited a new and efficient catalyst for luminol CL reaction. The CL enhancement of Mg-Al-CO3LDHs on luminol was due to the concentrating of luminol dianion and peroxide ion onto the LDHs surface by electrostatic attraction, resulting in their effective reaction with the intercalated carbonate. This study has successfully built a bridge between LDHs inorganic materials and molecular CL spectroscopy, which would urge interdisciplinary researchers to further investigate the influence of a variety of interlayer anions in LDHs on CL. It is believed that LDH-catalyzed CL has very large potential in chemical/biological sensing.2. Based on the enhancement of Mg-Al-CO3LDHs to luminol-H2O2CL, the first CL analytical application of LDHs was developed for the determination of H2O2in rainwater samples with good sensitivity and reproducibility. Therefore, Mg-Al-CO3LDHs can be used as a green catalyst for luminol-H2O2CL reaction. It was found that the CL intensity was proportional to the concentration of H2O2in the range from5×10-8to1×10-5mol·L-1, The detection limit of detection (S/N=3) was found to be as low as2×10-8mol·L-1and the relative standard deviation (RSD) for nine repeated measurements of1×10-6mol·L-1H2O2was2.9%. This proposed method has been successfully applied to detect H2O2in rainwater samples with good accuracy and precision. In comparison with previous luminol CL applications in flow injection systems, the present method exhibited highly sensitivity, simplification, environmental friendliness and low expenses for the determination of H2O2. The novel methodology is expected to provide a general protocol for the determination of H2O2as well as for numerous other oxidase-based reactions producing H2O2as a product (e.g., glucose).3. This work has developed a novel CL flow-through biosensor for glucose on platform fabricated by bienzyme network and luminol-hybrid LDHs. The silica sol-gel with glucose oxidase (GOD) and horseradish peroxidase (HRP) was immobilized in the first half of the inside surface of a clear quartz tube, and the luminol-hybrid Mg-Al-CO3LDHs were packed in the second half, which was constructed a CL flow cell, adjacent to a photomutiplier tube (PMT). In this case, the specific advantages of Mg-Al-CO3LDHs included the high buffering capacity and strongly catalyzing activity on the luminol CL, and thus a stronger light of the present system can emit in weak acid or neutral solutions by using this simple micro-fabricated device. This novel CL flow-through biosensor has been successfully applied to determine glucose in human plasma samples with simple procedure, shorter response time, high selectivity and wide pH compatibility.The proposed CL flow-through biosensor has very large potential in the assays of other analytes by tuning enzyme species.4. Turn-off chemiluminescence sensors through hydrogen bonding recognition have been clearly established in this work. We found that bright blue emission for the LDH nanosheets irradiated by the UV lamp (365nm). The fluorescence quantum yield of LDH nanosheets directly measured on the Edinburgh instrument was found to be41.3%. Serving as novel CL catalyst and CL resonance energy transfer acceptor (CRET), LDH nanosheet colloids can induce a significant increase in the CL intensity of bis(2,4,6-trichlorophenyl) oxalate (TCPO)-H2O2system. On the other hand, biogenic amines can selectively inhibit the CL intensity of the LDH nanosheet-TCPO-H2O2system as a result of inactivation of photoluminescence LDH nanosheets through the displacement of O-H-O bonding by O-H…N bonding. In addition, histamine is used as a common indicator of food spoilage, and it is found that the CL intensity is linear with histamine concentration in the range of1×10-7to1×10-4mol·L-1, and the detection limit for histamine (S/N=3) is3.2×10-9mol·L-1. The proposed method has been successfully applied to trace histamine evolution of spoiled fish and pork meat samples with simplicity, selectivity and sensitivity, displaying a time-dependent increase in the biogenic amines levels in such samples.