Fluorophores-modified nanomaterials for trace detection of polychlorobiphenyls and heavy metal ions

Fluorescence quenching approach, as an in situ and real time detection approach to specific pollutants, has received special attention for rapidity, simplicity, high sensitivity and selectivity. And it is reported that fluorophores-modified-nanomaterials exhibit much higher sensitivity than that of bare fluorophores in solutions. And the sensitivity can still increase with the surface to mass (S/M) ratio of the sensors, as a result of the better interaction between the fluorophores modified on the nanomaterials and the target molecules. Therefore, porous anodic aluminum oxide template with periodically arranged nanopore arrays, electrospun nanofibrous films with abundant micropores on their surface, nanowires/nanoparticles fabricated with high S/M ratio, and even porous peanut shells, are all selected as building blocks to assemble fluorescence sensors. In this review, the fluorophores that show particular fluorescence responses to specific molecules are conjugated onto the above-mentioned nanomaterials via simple adsorption, embedding or covalent bonding method. Then the obtained fluorescence sensing materials are used for fluorescence detection of environmental pollutants including polychlorobiphenyls (PCB101 and PCB20) and heavy metal ions (Cu2+, Cr3+, Cd-2+(,) Zn2+ and Hg2+) with high sensitivity and selectivity. We also proved that our fluorescent nanomaterials show much better sensing ability compared to bare fluorophores in solution. Furthermore, the obtained fluorescent nanomaterials are used to detect target heavy metal ions in polluted lake waters with satisfactory results, proving their practical application ability. (C) 2016 Elsevier B.V. All rights reserved.