[Study on three-dimensional fluorescence spectra of phenanthrene].
ABSTRACT According to the high fluorescence quantum yields of polycyclic aromatic hydrocarbons (PAHs), the fluorescence spectra of phenanthrene were investigated by three dimensional fluorescence excitation-emission matrix (3DEEM). The results show that the three-dimensional fluorescence spectra of phenanthrene in aqueous solution mainly have two fluorescence peaks. On the basis of three-dimensional fluorescence spectrometry analysis of phenanthrene, the excitation wavelength of 255 nm and emission wavelength of 273 nm were chosen for the quantitative analysis of phenanthrene. The linear range for the determination of phenanthrene was 5.0-250.0 mg x mL(-1), its detection limit was 3. 88 ng x mL(-1), and its relative standard deviation was 4.23% (n=5). It was a good precision. It has been tested satisfactorily for the determination of artificial sample in tap water. The recoveries are in the range of 90%-105%. The method provided basis for the rapid monitoring of trace PAHs in water.
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ABSTRACT: The present paper used synthesized data from the experiment samples to replace partial basic experiments, and increased the training samples amount from 14 to 27. In principal component analysis (PCA), the dimensionality of multivariate data was reduced to n principal components and almost all data information was kept. The PCA reduced the network's input nodes from 60 to 3 to simplify the neural network's structure. Finally, back-propagation neural network was used to train and predict these samples. It had 27 training samples, the input layer had three nodes, the hidden layer had two nodes, and the output layer had two nodes. Its excitation function is variable learning rate method. The results show that the coefficient of recovery can reach 89.6-109.0. It has reached the expected purpose.Guang pu xue yu guang pu fen xi = Guang pu 10/2010; 30(10):2780-3. · 0.27 Impact Factor