Theory And Application Of Electrochemical Analytical Techniques And Tobacco Flavor Chromatographic Fingerprint

Analytical science has experienced rapid progress in recent years, in particular, in the field of chemically modified electrode, piezoelectric quartz crystal microbalance, piezoelectric biological sensors and chromatographic fingerprinting technology where tremendous theoretical and applicapable achievements were obtained, which had greatly promoted the development in relevant subjects. In this work, the following research works were carried out on the basis of extensive literature investigation.1, The copper ion was directly determined by mercaptoethane sulfonate (MES) modified gold electrode in the presence of human serum albumin(HAS). The kinetic process of copper ion binding with HSA was studied through stripping voltammetry. A kinetic model with two consecutive steps was derived for the first time and used to depicting the binding process. The derived model was compared with the parallel kinetic respond model through using residual analysis. The experimental data of the striping peak currents were fitted with experimental time and the corresponding kinetic parameters were estimated: k₁=0.411 min^-1, k₂=0.055 min^-1.2, For the cyclic voltammetry study of a non-ideally reversible redox system, the ratio of anodic peck coulombic change against cathodic peak coulombic change in working electrode was a constant. Based on this fact, a new method was proposed for background discount in electrochemical quartz crystal microbalance application for the first time. The electrochemical oxidation behaviors of adenine, adenosine and adenosine monophosphate on gold electrode were investigated by this method. The results demonstrate that three molecule can be oxidized at about 1.2V, the order of corresponding oxidation currents was adenine >adenosine >AMP, and the number of transferred electron was six in this oxidation process.3, Characteristics of mutagenic growth of Salmonella trphimurium strain TA100 induced by sodium azide(NaN3) was investigated by piezoelectric impedance microbial sensing technique according to the fact that the viscidity and density of the culture system will change during the growth of microorganism. A corresponding mutagenic and poisonous/inhibitory model, ΔR₁ =am-bm^c + ΔR₀, was proposed to describe the mutagenic growth property for the first time. The experimental result shows that this model could be used to reflect the effect o f NaN₃ on microorganism growth. The mutagenic intensity and poisonous/inhibitory coefficients of sodium azide were obtained through model fitting. This work provided a new method for posting the mutagenic mechanism, investigating comprehensive effect of mutagen on the growth of microorganism and monitoring the mutagenic growth process.4^ Simultaneous distillation extraction (SDE) and solid phase micro-extraction (SPME) were used to extract volatile components in tobacco flavor. The characteristics, reproducibility and the result of quantitative analysis of these two methods were studied for comparison for the first time. The result shows that compared with the SPME method, the SDE method has better reproducibility and can provide more information for the analysis of volatile components in tobacco flavor, indicating that the SDE method is suitable for the quantitative analysis, quality control and chromatographic fingerprint establishment of tobacco flavor. However, the advantage of the SPME method is speedy, simple, solvent-free and non-destroyable,which is fit to qualitatively analyze volatile components in tobacco flavor.5> Volatile components in 32 the kinds of tobacco flavor provided by a cigarette factory were extracted with corresponding extraction methods, and their chromatographic fingerprints were established by chromatographic analysis for the first time. The similarity calculation and pattern recognition were applied to evaluate fingerprints and recognize different samples. The fingerprint evaluation and flavor recognition software of thirty-two were accomplished. This software has the advantage of low cost, short time, nicety and high reliability, flexible program and convenient data complementation.6^ The hexane was used as a solvent to extract flavor components in coffee flavor and the fingerprint of this extractant was established through gas chromatograph-mass spectrum method. The ratio of common peaks, the coefficient of variation for content of each components and similarity were adopted as indexes for the evaluation of six different batches of samples. The result demonstrates the good consistency between these samples, indicating the obtained chromatographic fingerprint can be used to implement the quality control of coffee flavor. The research also indicates that samples with a little of differences can be distinguished by similarity comparison and projection of principle component analysis.