Detection Of Nitro Aromatic Compounds In Beverages Based On Fluorescent Materials

2,4,6-trinitrophenol (TNP), which is one of the important nitroaromatic hydrocarbons,can be used for the preparation of dyes, explosives, and the paper industry as chemical raw materials, also is mainly pollutant in printing and dyeing industry waste water. Its biological persistence and intolerance degradation lead to genetic mutagenicity and toxicity. With the increasing severe worldwide counter-terrorism situation, TNP may be incorporated into the beverage by terrorists. Therefore, the development of TNP detection methods has a very important significance for security, food testing and sewage detection.In this study, a highly sensitive and rapid method for the detection of TNP based on rare earth upconversion fluorescent nanomaterials was developed. Based on the strong interaction between basic guanidine groups of guanidine-modified materials and acidic TNP molecules,the fluorescence of upconversion fluorescent material is quenched. The oil-soluble UCNPs with diameters of 80 nm were successfully synthesized by solvothermal method. UCNPs@NH2 was obtained by chemical modification of the obtained up-conversion nanoparticles by reverse microemulsion method, and further conversion of the ammoniated up-conversion nanoparticles to UCNPs@GDN. The prepared UCNPs were characterized by transmission electron microscopy (TEM), infrared spectroscopy (IR), X - ray diffraction (XRD), Zeta potential test and photoelectron spectroscopy (EDS). UCNPs have a good fluorescence property. When excited by 980nm light source, UCNPs@NH2 shows two fluorescence peaks at 550nm and 660nm, respectively. UCNPs@GDN displays three fluorescence peaks at 365nm, 479nm and 550nm, respectively. The effects of buffer system, pH value, detection time and other factors on the stability and sensitivity of the detection system were investigated. When the concentration of TNP was in the range of 10-5-10-12mol L-1, the change of fluorescence signal was linear with the change of concentration. The lowest limit of detection was 9.78×10-13mol L-1. Compared with nitrobenzene and nitrophenol, the method has high selectivity to TNP. Finally, six kinds of beverage samples were tested, which indicated that this method could be applied to the rapid and sensitive detection of TNP in beverages.