Study On Several Key Techniques Of High Performance Liquid Chromatography-Atomic Fluorescence Spectrometry And Its Application On Arsenic Speciation Analysis

Elements’ toxicity often related with the valence of the elements, the chemicalform or organic state. It is unscientific of only detect the total amount the elements tostudy its role on human health. With the rapid development of world trade, most ofcountries paid more and more attention to food safety problems, It is urgent todevelop efficient, rapid speciation analysis method to detect various species of everyelements in food.This thesis was aimed at performing technical support for the establish ofspeciation analysis method and the improvemence detection performance ofHPLC-HG-AFS system (High performance Liquid Chromatography-HydrideGeneration-Atomic Fluorescence Spectrometry). This thesis carried out mathematicalmodeling, data processing method, as well as sample preparation method from thepoint of view of instrumental analysis. The main tasks and main innovations includedthe following four aspects:1. Established mathematical model of the analysis system: There existed manyfactors impact the sensitivity and broadening of the spectral peaks of theHPLC-HG-AFS system and thsy were not isolated, This paper had abstracted out amathematical model for the process of hydride reneration, transmission and detectionand had established a function of the relationship of each parameter and sensitivity,peak broadening coefficient. The correctness of the model is validated by comparisonof the simulation results and the experimental data. On this basis, this thesis hadstudied the influence of the parameters to the sensitivity and spectral peak broadeningcoefficient using the model. Finally, this thesis had seeked the main factors impact thesystem, which would be very important to optimize the experimental conditions andto improve the instrument performance.2. Data Processing Method: HPLC-HG-AFS system is Combined the high-performance liquid chromatography with the hydride generation-atomic fluorescencedetection system. Generally, the data processing method was simplely adopted HPLCdata processing as Gaussian fitting,which would cause big deviation if ignored theinfluence of HG-AFS system. This paper was on the purpose of developing a"private" data processing method for HPLC-HG-AFS system according to its features.In this thesis, a new mathematical function was put forward to combine the HPLC and FI-HG-AFS system. The mathematical function was proved to be right throughapplying to fit the experimental spectral data. In combination with the differentialalgorithm, this thesis adopted the data processing method to process the overlappedspectral spectrum data. The result showed that this method effectively separated theoverlapped spectra and reduces the computational deviation. In summary, this methodcan effectively raise the correlation coefficient of the standard curve.3. Sample pretreatment methods of speciation analysis: This thesis adoptedaccelerated solvent extraction (ASE) method to extract different arsenic speciations infood of animal origin. The difficults of using accelerated solvent extraction method toextract different compounds in the food of animal origin was the conversion ordegradation of analytes in the extraction process. This thesis analyzed the feasibilityof the ASE method in principle on the factors of extraction solvent, extractiontemperature, extraction time and cycle times. Finally, thesis established the studymethods of the key problem of pre-treatment for speciation analysis.4. Establishment of HPLC-AFS method for the analysis of organic arsenicspecies in food of animal origin: Arsanilic acid, nitarsen and roxarsen was threewidely used veterinary medicine, this thesis established HPLC-HG-AFS method todetect the three organoarsenic species in food of animal origin. In this thesis, theHPLC mobile phase, concentration and flow rate of reducing agent and hydrochloricacid, voltage of photomultiplier, lamp current, the folw rate of carrier gas andshielding gas. Under the optimal instrument conditions, the limit of detection of thethree arsenic species were reached to0.24ng mL-1,0.74ng mL-1and0.41ng mL-1respectively. The RSD were all above94%in the real sample experiments. Theexperimental results showed that the method of detection of the organoarsenic apeciescould gain high sensitivity and reproducibility. This method could achieve a profoundimpact on chinese chemical speciation analysis work if develop further study toimprove the detection performance of the instrument.