The Determination Of Metal Irons By Gold Nanoparticle-based Optical Probe

With the development of industry and the acceleration of social life,some wastes containing heavy metals such as waste gas,waste solid and waste water are released into the ecological environment such as rivers,oceans and soils.The pollution caused by heavy metals is serious at present,which not only have effect on the ecological environment,but also does harm to the health of the organism.And it’s important to detect metal ions in order to protect the ecological environment,build a healthy ecological atmosphere.The traditional metal ions detection method is mainly based on large-scale instrument detection method and has advantages of high sensitivity,high precision,and good reproducibility.However,many shortcomings limit its real-time on-site inspection,such as high detection cost,long detection time and operation of professional technicians.In order to protect the environment,one rapid,simple and accurate approach for the detection metal ions is neccessary.Three kinds of nanogold（BSA-nanogold clusters,HEPES-tartaric acid-nanogold particles and nanogold particles）were synthesized to construct optical probes for Pb²⁺,Cu²⁺,Cr³⁺and Cr⁶⁺.In addition,one coloremetirc sensor array based on efforts of Au NPs and amino acid was successfully designed for the determination of 18 species metal ions（10μM）.The research result is as follows:（1）Nanogold clusters（Au NCs）fluorescent probe was established with the help of bovine serum albumin,which act as reducing agent and stabilizer.Pb²⁺can etch the BSA-Au NCs causing the disappearance of fluorescence in the presence of S₂O₃^2- and 2-mercaptoethanol（2-ME）.The result shows that the whole detection system possess good sensitivity and anti-interference ability.A good liner relationship between the changes of fluorescence intensity and the concentrations of Pb²⁺could be obtained in the range of 10 nM to 1μM（R²=0.9910）with the detection limit of 1.043 nM（S/N=3）.Moreover,real sample detection（lake water,tap water and sorghum extract）exhibits a good recovery rate（92.49%-111.69%）showing the potential practicality of this probe.（2）A fluorescent probe based on BSA-Au NCs etching was construct to detect Cu²⁺.In the presence of H₂O₂,SCN^-,NH₃,Cu²⁺reacts with the buffer solution forming Cu（NH₃）₆²⁺complex,which accelerates the decomposition of H₂O₂,thereby inhibiting the oxidative etching of gold nanoclusters by H₂O₂.The results indicate that the BSA-Au NCs fluorescent probe system is highly sensitive to a small amount of Cu²⁺showing a good linear relationship in the range of 5 nM-1.25μM（R²=0.9924）,and the actual detection limit is 5 nM.In addition,BSA-Au NCs probes have strong anti-interference ability and have achieved good recovery rates in urine,tap water and sorghum extract（103.6%-113.59%）.（3）A bifunctional nanoprobe called HEPES-tartaric acid-nanogold（HEPES-TA-Au NPs）was designed.The probe achieves 2-channel respective detection of Cr³⁺and Cr⁶⁺via the changes of ultraviolet absorption spectra Abs and?RGB（RGB is the representative of red,green and blue signals in the three primary color channels,?RGB was the changes of RGB）.Under optimal conditions,a good linear relationship between the Abs680 intensity and the concentrations of Cr³⁺could be obtained in the range of 0.01μM to 8μM（R²=0.9882）.In the naked eye detection,a good linear relationship between the Euclidean distance fromΔRGB and the concentrations of Cr³⁺could be obtained in the range of 0.1μM to 2μM（R²=0.9847）.For test the quantitative detection capability of Cr⁶⁺,a good linear relationship between the Abs680 intensity and the concentrations of Cr⁶⁺could be calculate in the range of 0.01μM to 4μM（R²=0.9958）.In the naked eye detection,a good linear relationship between the Euclidean distance fromΔRGB and the concentrations of Cr⁶⁺could be obtained in the range of 0.1μM to2μM（R²=0.9871）.In addition,the results of interference experiment and analysis of real samples showed the high selectivity and high accuracy of the proposed method demonstrating the potential for field application.（4）We report a new colorimetric sensor array based on amino acids regulated aggregation of Au NPs.Amino acids can regulate aggregation degree of co-existence mixture（Au NPs and metal ions）through weak bonds obtaining multidimensional signal characteristics.RGB values were caputured to continue principal component analysis（PCA）,cluster analysis（HCA）,discriminant analysis（LDA）.The result shows that the method has a good effect to discriminate more than ten metal ions.In addition,quantitative analysis of Cu²⁺detection was carried out.It was found that Cu²⁺have good linearity at 100 nM-2.5μM and 2.5μM-15μM.And the actual detection limit is100 nM.Meanwhile,good linear relationship and low detection limit showed the array is a promising and potential tool for real-time field metal ions detection.