Column Switching-ion Chromatography Method For Analyzing Complex Matrices

Ion chromatography (IC) is one of the most useful ways to analyze ionized compounds which can be operated easily and automatically. It is widely used in the area of food, environment, energy and medicine. However, When expanding the application of the IC system, the complexity of samples increased. And common sample pre-treatment methods can not meet the needs of the analytical works. Thus, establishing a new sample pre-treatment method of IC is of great significance. In this thesis, a column-switching ion chromatography system was proposed to analyze complicated samples.In Chapter 1, the overview of column-switching technique used in liquid chromatography is introduced. The application of column-switching technique in food, medicine and biological samples is described. IC-column switching system is highlighted and divided into two parts to illustrate including single pump column switching system arid double pumps column switching system.In Chapter 2, a simple ion chromatography with column-switching method was developed for the simultaneous analysis of monosaccharides and oligosaccharides in honeydew and nectar. A reversed-phase column called Ionpac NG1 was used as a pretreatment column to eliminate organics on-line and sugars were eluted from a collection loop to analytical column by using column-switching technique. This method showed good repeatability and was effective in removing water-soluble matrix in sample automatically.In Chapter 3, an ion chromatography with column-switching method was proposed for determination of fluoride in soil water extract. A reversed-phase column called Ionpac NS1 was used as a pretreatment column to separate fluoride and organic acids as well as eliminate organics on-line. Fluoride was collected by a collection loop and delivered to the analytical system to analyze. The method could be applied to determine fluoride in complicated samples with organic acid interference.In Chapter 4, an ion chromatography with column-switching technique was described for the simultaneous analysis of peroxydisulfate and conventional inorganic anions in surface waters. Conventional inorganic anions were separated by consecutive elution through both the guard column and separation column, but peroxydisulfate that only passed through the guard column had a good peak shape and short retention time. This method was not only accurate, reliable, but also realized to analyze peroxydisulfate which had strong retention time and conventional anions in short time.