Efficient Analysis Of Plant Growth Regulator By Pressurized Capillary Electrochromatography

Plant growth regulator(PGR),a kind of artificial synthetic pesticide,is widely used in our agriculturalproductions.Many pollutions of soil and water environment could happen with the excessive application of PGR,and lead to a potential residue of PGR in fruits and vegetables.It might cause pollution in food chain,and should be monitored strictly.Pressurized capillary electrochromatography(pCEC),a feasible method for trace analysis of artificial synthetic pesticides due to its simplicity and ultra-low sample and solvent consumption with high resolution and efficiency,has gained more and more attention.QuEChERS method,a general handling solution with easy,cheap,and effecient characteristics,has been used widely in food pretreatment.It is significant to form an efficient and rapid profile for PGR by combining with QuEChERS and pCEC.In this thesis,some electrochromatography separation behavior of PGRs has been evaluated,and a fast and highly efficient analysis of PGRs by pressurized capillary electrochromatography has been obtained.The mains contents are listed as below:In chapter 1,a literature review was shown.The background knowledge on PGRs was summarized,and the structure and nature of PGRs were also indicated briefly.The progress on the analyisis of those PGRs with high risk character was introduced,and then the topic and experiment contents off this work were put forward.In chapter 2,the electrochromatography separation behavior of some PGRs(Forchlorfenuron(viz.N-(2-Chloro-4-pyridyl)-N'-phenylurea,CPPU),paclobutrazol(PBZ)and 2,4-dichlorophenoxyacetic acid(2,4-D))was evaluated.Due to the difference of pKa values,dissociation ability and retention characteristics,the electrochromatography behavior of CPPU,PBZ and 2,4-D has been investigated with pCEC,and thus an efficient anlaysis method was established on the basis of a comprehensive mechanism including electroosmotic flow,electrophoresis migration and chromatography retention.In chapter 3,a new method for analysis of gibberellic acid(GA3),abscisic acid(ABA),2,4-dichlorophenoxyacetic acid(2,4-D),forchlofenuron(CPPU)and paclobutrazol(PBZ)was formed with pCEC system.Under the optimal conditions,the electromigration and chromatographicretention behavior of these above five PGRs on ODS capillary packed column was investigated in detail.A baseline separation of these PGRs was obtained rapidly in 9min with a range of LODs in 0.5?g/mL-5?g/mL.Coupling with a rapid QuEChERS pretreatment,the method was senstive and the LOD vaule ranged from 0.01 ?g/mL to 0.1 ?g/mL for GA3,ABA,2,4-D,CPPU and PBZ,respectively.Applied to fortified pear samples,the recoveries gained with pCEC were in the range from 72.9%to 105.8%for the direct detection,and from 88.5%to 113.0%with an enrichment handling,respectively.Compared with that obtained with LC-MS method,the results were acceptable.In chapter 4,a new method for fast analysis of carboxyl PGRs was developed via dipole interaction.Detail chromatography behavior and electricity chromatographic retention of GA3,ABA and 2,4-D in different mobile phases,in which various electrolytes including ammonium formate,sodium chloride,potassium chloride and sodium bisulfite,was studied.And the interaction mechanism between these electrolytes with rich elecronics group and ionic PGRs was discussed.Bu using the selected sodium chloride as the electrolyte in mobile phase,several parameters of the electrochromatography was optimized.Under optimal conditions,three analytes were separated efficiently and rapidly.The RSD of peak and retention time were less than 5.8%and 2.2%,respectively.Applied to furtified pear sample,the recovery rates could be gained in the range from 91.7%to 106.6%with RSD less than 6.7%.