Two novel topological electro-negativity indices based on distance matrix,named YC and WC indices,were proposed to be used for modeling properties of multiple bond organic compounds by equilibrium electro-negativity of atom and relative bond length of molecule.A quantitative structural property relationship(QSPR) model for estimating flash point of 92 compounds was developed based on the newly introduced topological electro-negativity indices YC and WC and path number parameter P3.The model correlation coefficient and standard error for training set in multiple linear regression were 0.9923 and 5.28,respectively.The average absolute error of flash point was only 3.86 K between experimental and calculated values,and the relative error was 1.46%.Furthermore,the model was strictly tested by both internal and external validations.The predicted values were in good agreement with experimental values for leave-one-out(LOO),and the training set and validation set.The results show that this QSPR model is of good stability and powerful prediction ability.
A novel technique of immobilizing indicator dyes by electrostatic adsorption and covalent bonding to fabricate optical sensors was developed.3-Amino-9-ethylcarbazole(AEC)was attached to the outmost surface of quartz glass slide via aminosilanizing the slide,crosslinking chitosan,adsorbing Au nanoparticle,self-assembling HS(CH2)11OH,and coupling AEC.Thus, an AEC-immobilized optical sensor was obtained.The sensor exhibits a wide linear response range from 7.0×10- 7to 1.0×10 -4 mol/L and a correlation coefficient of 0.995 9 for the detection of 2-nitrophenol.The detection limit and response time of the sensor are 1.0×10- 7mol/L and less than 10 s,respectively.The fluorescence intensity of the used sensor can be restored to the blank value by simply rinsing with blank buffer.A very effective matrix for immobilizing indicator dye is provided by the proposed technique, which is adaptable to other indicator dyes with amino groups besides AEC.
