| Reactive nitrogen species (peroxynitrous acid, ONOOH) can react with protein, DNA and enzyme in biosome, which can affect our health. Based on the ONOOH involved chemical reaction, the development of the sensitive and selective analysis methods for the detection of biological samples is a hotspot. ONOOH can be converted into nitric acid and produce chemiluminescence (CL). However, the signal is too weak to detect. Layered double hydroxides (LDHs) are a kind of environmentally friendly materials with unique structure and controlled layer cations and interlayer anions. Herein, LDHs have been introduced into the chemical reaction of ONOOH, which can induce a significant increase in the CL intensity of ONOOH system. The CL mechanism of the system has been studied. The effects of various factors on CL behavior of the system have been discussed. Combined with flow injection analysis technique, the sensitive, selective and rapid CL method was developed for the determination of trace substance. This success of this work expands the applications of LDHs in CL field.1. A CL method was developed for the determination of ascorbic acid in commercial liquid fruit juice using Mg-Al-CO3 LDHs-enhanced ONOOH as a novel CL system. It was found that the CL intensity from the ONOOH system can be significantly enhanced in the presence of Mg-Al-CO3 LDHs. The effects of the Mg/Al ratio, the reaction temperature, the aging time, the concentration of LDHs, the concentration of HCl, the concentration of H2O2, the concentration of NaNO2, and the flow rates had been studied. The enhancement mechanism of Mg-Al-CO3 LDHs on the ONOOH CL was discusssed. The enhanced CL signals resulted from the concentration of ONOO onto the LDHs surface by electrostatic attraction, meaning that ONOO can interact with the intercalated carbonate easily and effectively. Moreover, ascorbic acid can react with ONOO-, resulting in a decrease in the CL intensity from the Mg-Al-CO3 LDHs-ONOOH reaction. The CL intensity was proportional to the concentration of ascorbic acid in the range from 5×10-9 mol·L-1 to 5×10-6 mol·L-1 (r=0.9983). The detection limit (S/N=3) was 5×10-10 mol·L-1. This method has been successfully applied to determine ascorbic acid in commercial liquid fruit juices.2. Based on ONOOH-fluorescein dianion (FLUD) as a model CL resonance energy transfer (CRET) system, a universal CL flow-through device suitable for various CRET systems has been successfully fabricated. This fabricated CL flow-through column has been successfully applied to determine nitrite in sausage samples. The FLUD assembled LDHs were packed into a quartz tube, and then, the performance tests of this new CL flow-through column were carried out using ONOOH system in a flow-through CL setup column. FLUD on the CL flow-through column can significantly enhance the CL intensity of the ONOOH. The fluorescence microscopy images, Raman spectroscopy, steady-state fluorescence polarization measurements demonstrated that FLUD assembled upon the LDH surface could be arranged in an oriented and planar manner, where the intermolecular π-π stacking interactions among aromatic rings were suppressed. As a result, the energy transfer efficiency has been improved remarkably due to the increased fluorescence lifetime and quantum yield. Moreover, calcein assembled on the surface of the LDHs has great ability to enhance the CL intensity of the NBS-Na2SO3 system in comparison with calcein aqueous solution, which can further realize the generality of this CL flow-through column. This CL flow-through device exhibited operational stability, high reproducibility, and long lifetime.3. Based on embedding trace calcein molecules into the sodium dodecyl sulfate (SDS) bilayer bunches on the LDH exterior surfaces, a highly selective CL probe for ONOO-has been fabricated. The design was based on our new finding that the arrangement of calcein in the SDS bilayer bunches exhibited the delay effects with highly orderly and dispersive structure when the structure of LDH was collapsed in acidic solutions. The CRET process between ONOOH* donor and calcein acceptor was proposed based on fluorescence spectra, CL spectra, and UV-visible spectra. The conformational structure of calcein-SDS molecules was orderly after the structure of LDHs was collapsed in acidic solution. The as-prepared calcein@SDS solution could improve the sensitivity for ONOO- detection. In addition, the remarkable selectivity of the proposed probe toward ONOO- was ascribed to the energy-matching rules in the CRET process between ONOOH* donor and calcein acceptor. The proposed approach has been successfully used for the detection of ONOO-in cancer mouse plasma samples and decomposition reaction of 3-morpholinosydnonimine. |
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