Study On The Methods For Determination Of Metals Elements By Flow Injection Analysis And Low Pressure Ion Chromatography

With the development of society, especially the development of industry and technology, abundance of substance and wealth are created, at the same time, the environment was polluted seriously. Acid rain, greenhouse effect and ozone inanition had become the global concerned questions. A great deal of industrial waste and day life waste were discharged into the environment with the development of industry and city. Deleterious substance such as heavy metals, suspend substances, hydroxybenzenes and cyanide etc. are transferred and transformed into environment and polluted the atmosphere, soil and water, which furthermore done harm to the health of mankind. Heavy metals are the important contamination with latency harm.The characteristics of heavy metals' pollutions are as follows:(1) Minim heavy metals in water environment has toxic effects;(2) Microorganism can not consume heavy metals while some heavy metals will be transformed into organic compound which has stronger toxicity;(3) Organism can enrich heavy metals, with the raise of nourishment level, the concentration of heavy metals increased;(4) Heavy metals can be intake by the body with food, water and so on.Therefore, the determination of heavy metal is becoming much more important with the growth of mankind's understand. Because the heavy metals acted on organism and their non-biological degration character, heavy metals' contents had become an important index of appraising environmentalqualification. Heavy metals exist in different values in environment and different values have different action to mankind and environment. These substances are transferred, transformed and circle endless made the determination of heavy metals have larger challenge.At the present time, determination of heavy metals is usually by AAS, the precision of AAS is high and the veracity is good, it is a good method. While the price of apparatus is expensive and operation is fussy, AAS does not fit the in suit analysis, so the aim of the thesis is to establish the simple method which suit for locale analysis for determination of heavy metals.The work of this paper was divided into two parts.The first part is study on the determination of Chromium (VI) and Chromium (III) in seawater and Chromium (VI) and Iron (III) by reversed automatic reference flow injection analysis. And the determination of Cadmium( II) in seawater and copper( II) in industrial waste by FIA with new system.Flow injection analysis produced in 1970s', because of its high automatization, speediness, good choice and good repetition and it can join with many detections, it arouses a lot attention of chemical workers.Presently, the standard method for determination of Chromium (VI) in seawater is Diphenyl Carbazide spectrophotometry, this method is handwork and the operation is miscellaneous. To determine Chromium (HI) in seawater, oxidant is used to oxide Chromium (HI) to Chromium (VI). So it is not fit in suit analysis.There are many factors that affect the determination of Chromium (III) and Chromium (VI) in seawater. In order to eliminate the interference, a new method-automatic reference flow injection analysis was developed to determine Chromium (III) and Chromium (VI) . The optimum experiments including oxidant, colour-developing solution, reductometry solution and the length of reaction coil and so on are investigated. The method could be applied in the determination of Chromium (III) and Chromium (VI) in seawater successfully. The recoveries of Chromium (III) and Chromium ( VI)of seawater were 92.0-106.0% and 100.0-102.0% respectively. The RSD's of Chromium (III) and Chromium (VI) were 1.24-1.63% and 2.71-3.64% respectively.Cadmium( II) of seawater is an important detect target. A new method was established to determine Cadmium( II) in seawater by Butyl-RhB-FIA-spectrophography .Cadmium (II) in seawater is concentrated by a new concentrated column, and pulse solution is 5.0><10'3mol/L HNO3, Butyl-RhB is color-developing agent. The linear range is 0.50-12.0|ig/L and detect limit of method is 0.05u.g/L. The method is applied to determine Cadmium( II) in seawater samples with satisfactory results.In addition, a new method was proposed to determine trace Chromium (VI) and trace Iron (III) in chrome tanning by automatic reference flow injection analysis. Because there is large of Chromium (III) in chrome tanning, its deep colour affect the determination of other metals seriously.The interference of colour can be automaticly eliminated by automatic reference flow injection analysis. The colour-developing reagent is Diphenyl Carbazide, acetone and sufuric acid mixture, and the reductometry solution is acetone and sufuric acid mixture. The effects of concentration of Diphenyl Carbazide, the kinds of acid, flow rate were investigated. Under the optimum conditions, the detect limit and RSD of the method were 0.28ug/L and 1.24% respectively. The method was applied to the analysis of chrome tanning with satisfactory results. And while determining trace Iron (III) in chrome tanning, the colour developing reagent is sulfosalicylic acid and ammonium sulfate mixture and the reductometry solution is ammonium sulfate. The effects of concentration of sulfosalicylic acid and ammonium sulfate, the length of reaction coil and flow rate were investigated. Under the optimum conditions, the detect limit and RSD's of the method were lOug/L and 0.79% respectively. The method was applied to the analysis of Iron (III) in chrome tanning with satisfactory results.Spectrophotography is a common method for determination of Copper( II). Recently, determination of Copper( II) had a breakthrough withthe appearance of new color-developing reagents and new analytical instruments. Determination of Copper( II) with Diphenyl Carbazide and cetylpyridinium bromide (CPB) mixture as colour developing reagent and deion water as promote solution by flow injection analysis was studied. The effects of concentration of Diphenyl Carbazide, the kinds of acid, flow rate were investigated. Under the optimum conditions, the linear range and the detect limit of the method were 0.0~6.0mg/L and 0.050mg/L respectively, and RSD of the method was 1.04%. The method was applied to the analysis of industrial waste with satisfactory results.The second part is studying on determination of heavy metals by low-pressure ion chromatogram and its application.Chromatogram technology is a flourish method in modern trace analysis. It is applied widely in detection of anion, cation, biology molecule and medication synthesize fields. Generally, ion chromatogram must work under high-pressure system. It need pipeline, valve, bump, column and tie-in to endure high pressure and endure strong acid and base. While the work pressure of low-pressure ion chromatogram is lower and it can work at 200~300Kpa which is 1/100-1/50 of high-pressure system. It need not use expensively high-pressure pump and nitrogen bottle, which reduce the question of leakage and jam. The apparatus of low-pressure ion chromatogram is cheap and small.The main contents and some conclusions of this part are as follows:1. Simultaneously determine Fe (IIIX Cu (II X Ni (II X Zn (II X Co (II X Fe (II ) by low pressure ion chromatography (LPIC). The optimum chromatographic conditions are studied thoroughly. The RSD's are all less than 1.5%. Recoveries tested by the standard addition method are in the range of 96.0-105.6.0%. The method was applied to determine the environmental samples with satisfactory results.2. Methods for determination of Pb(II), Cu (II) and Zn(II) were established respectively. The method is less disturbance n simple and high sensitivity. These methods which analysis heavy metals in seawater directlywithout complex pre-treatment. The experiment conditions are as follows:(1) The separation column are all 1# column for Pb(II), Cu (II) and Zn(II), respectively. And 0.0075 mol/L oxalic acid-0.010 mol/L citric acid is eluent for Pb(II), the eluent of Cu (II) and Zn(II) are both 0.0060 mol/L oxalic acid-0.0080 mol/L citric acid. The colour-developing reagent for Pb( II), Cu ( II) and Zn( II) are all 1.5mol/L ammonia -0.5mol/L-acetic acid -lxlO^mol/L pyridine-(2-azo-4)-resorcinol. The flow rate of eluent and colour-developing reagent are all 0.6mL/min. The size of concentrated column is 80-1 OOum and the length of concentrated column is 60mm for Pb(II), the concentrated velocity is 5.0mL/min and the desorption time is 5min; The size of concentrated column is 60~80um and the length of concentrated column is 50mm for Cu (II), the concentrated velocity is 3.0mL/min and the desorption time is 4min; The size of concentrated column is 80-1 OOum and the length of concentrated column is 80mm for Zn (II), the concentrated velocity is 2.0mL/min and the velocity of desorption is 5mL/min.(2) Under optimium experiment conditions, the linear of Pb (II) and Cu (II) are both 0.0~50.0ug/L; The linear of Zn (II) is 0.0-1 OO.Oug/L. The method can analysis I -IV kinds of seawater.(3) The precisions of Pb( II), Cu (II) and Zn( II) are all less than 5%. The method was applied to determine Pb( II), Cu (II )and Zn( II) in seawater with satisfactory results.(4) The salinity interference experimentation shown that it had no interference on determination of Pb( II) and Zn( II), but had interference on determination of Cu( II).