Study On Determination Of Seven Anions By Modeling Of Ion Chromatography Retention And Its Application In The Determination Of Three Ethnic Medicines

Ion Chromatography determinates iconicity has several advantages such as rapid, convenient, sensitive and of high selectivity , the separation column has high stability and capacity and it can be used to multi-components determinate simultaneously. Ion chromatography has been widely applied in water quality testing, pharmaceutical analysis, chemical food, tobacco, beverages and other fields in recent years. Ion Chromatography retention value models were established in this thesis, which predicted anion retention value and optimizes chromatograph conditions. The thesis mainly took Hypericum patulum Thunb, Arundina graminifolia, Gardneria multiflora Makino as research objects, and then studied extraction analysis methods of water-soluble anion and simultaneous determination of total amount of fluorine, chlorine, bromine, nitrogen, phosphorus, and sulfur in traditional medicine.By studying relationship between eluent system of sodium carbonate - sodium bicarbonate and retention value, a retention model of ion chromatography was established. The calculation method of the model compiled Visual Basic with the user program. Through studying of relations between ion retention and efficiency of separation, then get eluent concentration–flow velocity model. Using this model for getting the optimal chromatographic conditions that eluent respectively is 3.50mmol/LNa₂CO₃,2.80mmol/LNaHCO₃,flow rate 1.40mL/min. We also studied the optimum flow rate selected ion chromatography method in modeling process. Predicted value of anion F^-, Cl^-, NO^2-, Br^-, NO₃^-, PO₄^3-, SO₄^2- and the experimental amount of relative standard deviation are respectively less than 3% and 4% in Chromatography retention model and eluent concentration - flow velocity model. Results showed that could more accurately predict the order of seven anions'peaks, retention and separation. This experimental model saved experiment cost, reduced the experiment quantity, fast calculation speed when conditions changed, and also improved the analytical speed.The thesis studied the oscillation extraction, ultrasonic extraction, matrix solid phase dispersion, ultralow temperature extraction of soluble anions in Hypericum patulum Thunb for extraction conditions and influencing factors, and improved matrix solid phase dispersion extraction device, studied on its operating conditions of extraction and purification conditions after improvement. The four extraction methods results show that: the optimal extraction conditions for oscillation extraction: particle size is 80 mesh, the minimum sample intake is 0.013g, extraction solvent is 8.0mL, extraction temperature is 24℃(room temperature); the optimum extraction conditions for ultrasonic extraction: solid-liquid ratio Hypericum patulum Thunb samples is 0.0500g and water is 5.00mL, ultrasonic time is 35min, ultrasonic power 320W, extraction times twice ,the amount of sodium carbonate added is 3.00mmol/L 0.50mL; the optimal extraction conditions for matrix solid phase dispersion: dispersant respectively are SPE C18 or SPE C18 and carbon, mixed dispersant are SPE C18 0.35g and carbon 0.04g, eluent 8.0mL, elution times once; the optimal extraction conditions for ultralow temperature extraction: extraction solvent is liquid nitrogen, dry extraction, extraction twice, the extraction time is one minute. The recoveries were range from72% to95% in four extraction methods, the method precision within 10%. The methods using the statistical functions KSTEST of Matlab to evaluate the reliability, the results show that the four extraction methods feasible and data reliable.The determination results show that the mixture double-alkali fusion of sodium carbonate and magnesium oxide melt samples (samples with low-level mixed alkali flux, surface layer coverage of alkali flux samples to prevent evaporation) better than do alkaline using sodium hydroxide flux. From investigating alkali fusion and influence factors, the alkali fusion temperature is range from 580℃to 600℃, the amount of alkali flux is 0.500g, alkali fusion time is range from 55minutes to 60minutes, the determination of total fluoride, total chlorine, total bromine, total nitrogen, total phosphorus, total sulfur analysis needless to purification, determined directly after filtration, the Ion Chromatographic peak separation was good, and no interference. The recovery rate was range from 70% to 85%. It is an ideal analytical method for determination total fluoride samples, total chlorine, total bromine, total nitrogen, total phosphorus, and total sulfur.