A peak-width quantitation method for flow-injection microwave plasma torch atomic emission spectrometry was proposed. Sensitivity and linearity of the peak-width quantitation were investigated under different emission intensities. Recoveries of Zn2+, Cu2+ and Ag+ existing in various matrix were determined by using the peak-width quantitation, and were compared with the results obtained by the peak-height method. The results indicated that the peak-width quantitation can efficiently remove matrix interference in the FI-MPT-AES system, and expand its linear determination range. The peak-width quantitation (recovery: 92%-107%) surpasses conventional peak-height method (recovery: 61.3%-122%). Optimized determination conditions were as follows: the sampling volume was 350 mL, the flow rate of the carrier was 1.5 mL x min(-1), the power of microwave was 110 W, the flow rates of the carrier gas and working gas (argon) were 1.4 and 0.4 L x min(-1), respectively.
Fourteen diphenyl ether and diphenyl sulfide compounds were synthesized and a comparative study on their second-order nonlinear optical properties was carried out. The results showed that these two kinds of compounds all had fairly large molecular first-order nonlinear optical hyperpolarizabilities β, but they have very different second harmonic generation (SHG). The diphenyl sulfide derivatives usually have strong SHG effects while almost all the diphenyl ether compounds have no SHG response, which can be attributed to their crystal structure. We found that the diphenyl sulfide compounds were easy to crystallize in a noncentrosymmetric style but the crystal structure of the diphenyl ether derivative was centrosymmetric, and therefore a zero χ(2) was produced. The atom O or S was the real origin of the difference in their crystal structures, and therefore of the SHG effect.
Eight synthesized Schiff base derivatives have been studied on fluorescence properties,the fluorescence spectra of them were determined,and results showed that only three chemical compounds respond obviously the fluorescence.We have studied systematically the law of structure of eight chemical compounds,and the molecular structures of them were optimized by quantum mechanics semi-empirical method called AM1,the results showed that different substituent,different length of conjugate chain and coplanarity of molecular have impacts to fluorescence properties of this type of Schiff base chemical compounds,which provide foundations for further molecular design of fluorescence materials.
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