| Ion Chromatography (IC) is a branch of Liquid Chromatography, it’s mainly used for the determination of cations and anions. IC has the advantage of high sensitivity, good selectivity and can be used for the simultaneous determination of multiple components. It has gained a quick development since invented in1975. IC plays a quite important role in the field of food, environment, agriculture, medicine, chemical industry and so on. It is the standard method of many common ions. With the development of chromatographic columns and detectors, the appliance field of IC widens from the determination of common ions to carbohydrates, organic acids, amino acids and so on. Ion exclusion chromatography is an effective method in the determination of organic acids. The determination of carbohydrates by high performance anion exchange chromatography with pulsed amperometric detection (HPAE-PAD) is a new method which is developed in recent years. HPAE-PAD has been widely used in the determination of carbohydrates in the field of food processing, health care products and so on, but research breadth and depth is not enough.The thesis consists of five parts. The first part is a review related to the development of IC technology and the simple introduction of classification, existence, application and analysis method of organic acids and carbohydrates. The others are composed of four parts as follows.1.. Determination of gallic acid in green tea by ion exclusion chromatography with conductivity detectionAn ion exclusion chromatographic method for the determination of gallic acid in green tea was described. The optimal chromatographic separation conditions were investigated on Metrosep Organic Acids (250mm×7.8mm) column with conductivity detection. The optimal separation was achieved with0.006mmol/L sulfuric acid as the eluent,50.0mmol/L lithium chloride as the regenerated liquid, the flow rate was0.5mL/min.There was no interference on the determination of gallic acid when fluoride and eight kinds of acids which could be easily found in green tea existed.The total analysis time was19minutes. The detection limit of gallic acid was0.1μg/mL. The RSD of peak area for the six consecutive determinations was1.34%.The recovery percentages of gallic acid in four kinds of green tea were87.1%～96.7%. The method was simple and rapid. The results were satisfied.2、Determination of soluble sugar in honey pomelo tea by ion chromatographyA method for the determination of soluble sugar in honey pomelo tea by high performance anion exchange chromatography with ultrasonic extraction and amperometric detection (HPAE-PAD) was described. The separation conditions were investigated on METROSEP CARB1(150mm×4.0mm) column.The optimal separations were achieved with5.0mmol/L NaOH as the eluent at the rate of1.0mL/min. The detection limits of sucrose, glucose, and fructose were0.2μg/mL,0.1μg/mL, and1.0μg/mL, respectively. The RSDs of peak height for the six consecutive determinations were1.56%～3.40%.The recovery percentages were86.80%～98.80%.The method was simple for sample pretreatment, the sensitivity was high and it provided a simple and effective method for the inspection of quality of honey pomelo tea.3、Determination of trehalose in cosmetics by ion chromatographyAn analytical method based on high performance anion exchange chromatography with pulsed amperometric detection (HPAE-PAD) had been established for the determination of trehalose in cosmetics. Different kinds of sample pretreatment methods were adopted. The samples were analyzed by ion chromatography with METROSEP CARB1column (150mm×4.0mm).200.0mmol/L NaOH was used as the mobile phase for elution. The samples could be analyzed within7min. The detection limit of trehalose was0.02μg/mL. The RSD of peak area was0.17%, and the RSD of retention time was0.28%. Glycerol and propylene glycol which could be easily found in cosmetics had no interference on the determination of the trehalose. The average recoveries were97.4%-98.8%.4、Determination of lactose、stachyose、glucose and sucrose in milk by ion ChromatographyA method was developed for the determination of lactose、stachyose、glucose and sucrose in milk by ion chromatography. Citric acid was used for the precipitator of samples. The samples were analyzed on a METROSEP CARB1(150mm×4.0mm) anion exchange column at32℃and were eluted with7mmol/L NaOH solution at a rate of1.2mL/min. The signal was detected by pulsed amperometric detector. The detection limits of0.1μug/mL～0.3μg/mL were achieved under the optimal conditions. The RSDs for the six consecutive determinations were1.60%～3.85%. The average recovery percentages of the samples were88.00%～101.00%.The method was simple and the resolution was good. It could be used in the determination of carbohydrates in milk. |
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