The Development Of On-line Automatic Monitoring Instrument For The Concentration Of Heavy Metal Ion In Water Based On ASV

With the development of society, the concentration of heavy metal ion in lakes,reservoirs, oceans and other water resources has been sharply increased， thecontamination called heavy metal ion in water quality has brought great affect onhuman health and social development. A little of heavy metal ions in water will be agreat toxicity, heavy metal ions is difficult to be degraded and readily absorbed byorganisms, drinking the water containing traces of heavy metal ions is likely to havekidney, liver, nervous system, causing serious damage to a serious threat to humanhealth, on-line monitoring the concentration of heavy metal ion in water has becomingimperative.The current direction of development on water quality in the internationalmonitor are: on-line, continuous, stable, high-precision, integrated. Therefore, thedevelopment of new high-sensitivity sensor, integrated water quality monitoringsystem for the concentration of heavy metal ion, the development of real-time onlineautomated heavy metal ions in water quality monitor has become an inevitable trend.By studying test methods and the characteristics of existing instruments for theconcentration of heavy metal ion in water, proposing a BDD (Boron Doped Diamond)electrode electrochemical sensor for the new ASV (Anodic Stripping Voltammetry)instrument for monitoring of heavy metal ions.In order to compensate for atomic spectroscopy, mass spectrometry andspectrophotometric methods, select the applicable water quality line automaticmonitoring for the concentration of heavy metal ion， electrochemical analysismethods-anodic stripping voltammetry, in order to improve the precision monitorsfurther，using square wave and differential pulse anodic stripping voltammetry.Monitor hardware includ instrumentation design unit, power design unit, processdesign unit. PC using ARM Cortex-A8, low-power, high-speed, low-cost multi-coreprocessors, the crew of the constant voltage source and a weak current acquisitionscan processing part uses a high-speed DAC, ADC, and other high-performance chips for testing monitor resolution and stability foundation. Process design unit is mainlyto complete the entire measurement cycle carrier, and monitor the results of themonitoring data, which advanced to the BDD electrode constructed three-electrodeelectrochemical sensor system, the unique design of the new integrated electrolyticcell reagents dosing device using a peristaltic pump injector accurate. Power supplyunit is designed to work properly the monitor base, in order to improve the monitoringaccuracy of the instrument, in the design of low noise, low power part of the ripplecharacteristics.The software of monitor includes two parts：management control and dataprocessing and analysis, management control section discusses the implementationmonitoring and control functions during the test, data processing and analysis sectiondiscusses the data collected from the line of I-V and the solution of spectrum peaksearch method to get the final results of the measurement.Monitor achieved by ARM+MCU+DAM combining with external measuringinstruments can be able to effectively monitor the real-time data; make monitor BDDelectrode ASV-based method can measure a variety of heavy metals, and exhibit goodstability; high-performance scanning constant current source and a weak signalacquisition and processing unit increases the resolution of the test instrument;integrated by new design of the cell improves the modularity of the instrument;through the data from the line of I-V effectively improve the monitoring capabilitiesof the instrument. The stability of the test results and the relative standard deviation ofmonitor has reached a certain degree of precision.