Study On The Determination Of Ammonia Nitrogen And Phosphorus Compounds In Water By Ion Chromatography

Water eutrophication is one of the common problems of water environment.Nitrogen and phosphorus compounds are important factors of eutrophication.Nitrogen and phosphorus compounds exist in various forms in the water,accumulate in the sediments of the water area and release from time to time.Therefore,the monitoring of nitrogen and phosphorus compounds in water and sediment has a certain significance of environmental monitoring.Ion chromatography(IC)is one of the effective methods for the analysis of various ionic compounds.It is widely used in many fields such as environment,food,energy,medicine and chemical industry.In this paper,the content of ammonia nitrogen and peroxydisulfate in water was determined by dual system ion chromatography and the degradation of peroxydisulfate was also studied.In addition,accelerated solvent extraction technique was used in the determination of inorganic orthophosphate and polyphosphate in sediments.The main research consists of the following five chapters.In Chapter 1:we introduced the general situation of nitrogen and phosphorus compounds and study the methods of ammonia nitrogen,peroxydisulfate,inorganic orthophosphate and polyphosphate.In chapter 2:A new method for simultaneous determination of ammonia nitrogen and peroxydisulfate in lake water was developed.Under the condition of heat,ammonia nitrogen was decomposed by peroxydisulfate.Then they were detected by double ion chromatography respectively with methane sulfonic acid and potassium hydroxide as eluent and suppressed conductivity detection.The method has been applied to the simultaneous determination of cation(ammonianitrogen)and anion(peroxydisulfate)in lake water.In chapter 3:The soil and sediment in the eutrophic water environment were collected,then dealed and extracted by optimized conditions of accelerated solvent extraction.Samples were analyzed directly after microporous filter and pre column.In accordance with the simple to complex,from isocratic elution to gradient elution order,ion chromatography conditions were explored for phosphorus compounds.1:IonPac AS23 was used as the anion analysis column.Meanwhile the Na2CO3-NaHCO3-NaOH solution system was used as eluent.The simple,practical and reliable method can be applied to the determination of phosphate and phosphite in eutrophic water.2:Trace pyrophosphate and other conventional anion in soil were simultaneously detected by automatic regeneration conductivity detector in 14 min with IonPac AS11 as analytical column,potassium hydroxide as solution gradient elution.3:Tripolyphosphate,common anions and partial phosphorus compounds(phosphite,phosphate,pyrophosphate,trimetaphosphate)in lake sediments were detected by suppressed conductivity detection in 40min simultaneously,by used IonPac AS19 high capacity anion exchange column as separation analysis,online KOH as gradient elution generated automatically.Through the separation,precision and accuracy indicators,the detection(IonPac AS19 column and KOH gradient elution)was the best choice,simple and effective.It was suited to carry out a variety of compounds containing phosphorus(phosphate,phosphate,pyrophosphate,tripolyphosphate)and conventional anion.