Construction Of Nanoprobe And Its Application In Detection Of PCB77

With the continuous improvement of requirement for environmental pollutant detection,the new analytical and detection technologies for persistent organic pollutants in the atmosphere,water and soil had become a hot spot in scientific research.In this study,by the high sensitivity,simple preparation and strong specificity of nanoprobe,two kinds of chemical sensors were designed and synthesized to respectively using fluorescence spectrophotometer and atomic absorption spectrophotometer to detect 3,3'4,4'-tetrachlorobiphenyl.The specific experimental content was as follows:?i?The fluorescence probe P1 was designed and synthesized by using the photoluminescence of carbon quantum dots which were synthesized by hydrothermal method and the specific recognition of aptamer chains and the synthesis conditions were optimized by the analysis of fluorescence properties.The design procedure of the fluorescence probe P1 was reasonable,the synthesis method was simple.?ii?The fluorescence probe P1 was used to detect 3,3'4,4'-tetrachlorobiphenyl in the actual samples.The experimental results showed that the fluorescence probe P1 which detected3,3'4,4'-tetrachlorobiphenyl with good selectivity and sensitivity.As a result,when the concentration of 3,3'4,4'-tetrachlorobiphenyl were from 1.0×10^-99 mol L^-11 to 1.0×10^-88 mol L^-11 and from 1.0×10^-77 mol L^-11 to 3.0×10^-66 mol L^-1,there was a good linear correlation between the fluorescence intensity of the solution and the concentration of 3,3'4,4'-tetrachlorobiphenyl.The detection limit could reach 7.6×10^-1010 mol L^-1?S/N=3?.The spiked recovery rate was 87.0%and90.0%.The relative standard deviations were all within 3%.At the same time,the fluorescence probe P1 exhibitsed specific recognition for 3,3'4,4'-tetrachlorobiphenyl.?iii?The cadmium telluride quantum dots were directly synthesized in the aqueous phase.The aptamer chains which had specific recognition and cadmium telluride quantum dots which had special fluorescence properties were used to synthesize the chemical sensor P2 for the analysis anddetectionof3,3'4,4'-tetrachlorobiphenyl.Whentheconcentrationof3,3'4,4'-tetrachlorobiphenyl was from 1.0×10^-8mol L^-11 to 1.5×10^-6mol L^-1,there was a good linear relationship between the absorbance of the solution and the concentration of3,3'4,4'-tetrachlorobiphenyl.Its detection limit could reached 1.5×10^-9mol L^-1?S/N=3?.For the detection of 3,3'4,4'-tetrachlorobiphenyl in the actual samples,the results showed that the recoveries were from 92.0 to 100.0%,and the relative standard deviations of the experiments were also controlled within 3%.The coexisting interference experiment and the specific detection experiment show that the chemical sensor P2 had the abilities to distinguish other polychlorinated biphenyl homologs.The whole experiment was simple in operation,low in cost,and had good selectivity and sensitivity.