| Summary: | 碩士 === 國立中興大學 === 機械工程學系所 === 106 === In this study, a portable electrochemical potentiostat and disposable gold electrodes were used to develop a real time heavy metal analyzer. The heavy metal analyzer is able to determine trace level of zinc in water. Square wave anodic stripping voltammetry (SWASV) was applied to characterize the real time heavy metal analyzer. First, zinc ions were deposited onto the surface of disposable electrodes by applying the reduction potentials and then deposited zinc were stripped through a square wave potential sweep. In the electrolyte with 1 mM HCl and 0.5 M NaCl, a reduction potential at -1300 mV for 90 sec was used to deposit zinc on disposable gold electrodes. After resting step 15 sec, the oxidation currents at -600mV were used to quantify zinc in the water.
The heavy metal analyzer is able to detect zin in the water from 0~5000ppb and has good sensitivity and low detection limit. The detection concentration can be divided into two intervals of 0~1000ppb and 1000~5000ppb. The linear regression equation for 0~1000pp is y=0.0768x+ 47.828 with an R2 value of 0.9756. Standard deviation was 1.11 (n=3). The detection limit is 47.7 ppb. The linear regression equation for 1000~5000pp is y=0.0221x+96.765 with an R2 value of 0.9782. Standard deviation was 1.66 (n=3). The detection limit is 247.9ppb. To investigate the selectively of zinc, Pb2+ and Cu2+ were used to examine in this study. There are slightly changes of oxidation peaks when water has Pb2+ or Cu2+ . The oxidation peaks reduced 13.3% and 16.5% when 10ppb and 100ppb Pb2+ were added in the water. The oxidation peaks reduced 18.5% and 17.1% when 10ppb and 100ppb Cu2+ were added in the water. Standard addition method was used to calibrate the heavy metal analyzer.
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