Computer Simulation For Moving Precipitation Boundary (MPB) And Its Preliminary Application

Analysis and detection of heavy metals have become increasinglyimportant because heavy metals are becoming more and more harmful tohumans and the environment, but the conventional analysis methods ofheavy metals have some drawbacks, such as high cost and poor sensitivity.Therefore, it is particularly urgent to establish a simple and effectivedetection method for analyzing heavy metal. Recently, the theory andexperimental for Moving Reaction Boundary (MRB) have beendeveloped rapidly and become a hotspot in the bioanalytical chemistryfield, and it has been applied to the separation and analysis ofbiochemical samples, such as zwitter electrolytes, proteins and clinicaldrugs. Moving Precipitation Boundary (MPB) as one of important partsof MRB, has the advantages of low cost, less demanding on theequipment and high efficiency enrichment in the stacking and analysis ofmetal ions. However, due to the complex reaction system andcomplicated optimization, the research of MPB should be improved.The paper considted of two parts. The first part: using OH-and copper to form the precipitation boundary combined with thecorresponding electrophoretic dynamics and electrochemical equations,we improved the mathematical model of MPB. In order to avoid thedetermination some experimental parameters which were difficultlymeasured, facilitate the calculation, and to forecast what may happen, wedesigned and achieved the computer simulation software correspondingto MPB model through assemble language Borland Delphi7compiler inthe Windows platform, and then we developed an effective dataprocessing and dynamic simulation program. The MPB simulationsoftware we redacted had two main purposes. First, according to themetal ion and other system parameters which the user inputs, the MPBsimulation software could quantitatively describe the concentration ofproduced precipitation,the velocity,the direction of moving boundary,theresolution of two metal ions and the stacking efficiency. Second, wecould dynamically simulate occurrence of MPB and evolutionary processon the basis of the calculation results of software. So the software couldbe used to predict the results of the MPB enrichment of metal ions andoptimize the experiment conditions.The second part: the verifications of the accuracy and reliability ofthe software by the MPB experiment in large tube. We designed threesystems:(1) the reaction system of MPB without elution ion;(2) thereaction system of MPB with elution ion; and (3) the reaction system of MPB containing two metal ions. The results demonstrated that theexperiment results were generally in accordance with the simulation indifferent systems; when a low concentration of metal ion was chose, agood stacking effect would be obtained in the second system. And0.1mMcopper could be enriched up to308-fold.The simulation software of MPB we researched and developed inthis paper can simplify the experimental process, reduce the workload ofresearch, and significantly improve the efficiency research for MPB; andit can design the most optimal enrichment condition to enrich trace metalions according to the stacking requirements,provide a method for offsetthe drawback of the conventional analysis methods of heavy metal.