Quantum dots in organo-modified layered double hydroxide framework-improved peroxynitrous acid chemiluminescence for nitrite sensing

In this study, the directional luminescent quantum dot (QD)-layered double hydroxide (LDH) assembly was fabricated by embedding the trace QDs onto the exterior surface of the organo-modified LDHs. It was found that this novel nanomaterial was able to extraordinarily improve an ultra-weak chemiluminescence (CL) emission from peroxynitrous acid (ONOOH). The enhanced CL emission was attributed to the electrostatic concentration of peroxynitrite (ONOO-) onto the orderly surface of the QD-organo-modified LDHs as well as the hydrophobic microenvironment of the organo-LDHs, facilitating the production of superoxide radical (O-center dot(2)-) and hydroxyl radical ((OH)-O-center dot). In addition, the CL intensity increased with increasing the concentration of nitrite in a wide range of 1.0-1000 mu M with a detection limit of 0.3 mu M (SIN = 3). Therefore, the proposed method was applied for the selective and sensitive detection of nitrite in sausage samples. Recoveries from spiked real samples were in the range of 96-103%. The results of the proposed method for sensing nitrite in real samples were agreed with those obtained by the standard spectrophotometric method. (C) 2013 Elsevier B.V. All rights reserved.