Voltammetric detection of the toxic Zn ion was investigated using a fluorine-doped graphite pencil electrode (FPE). It is notable from the study that pencils were used as reference and working electrodes. In all the experiments, a clean seawater electrolyte solution was used to yield good results. The analytical working range was attained to 10 microgL-1. The optimized voltammetric condition was examined to maximize the effect of the detection of trace Zn. The developed sensor was applied to an earthworm's tissue cell. It was found that the methods can be applicable to in vivo fluid or agriculture soil and plant science.
Agriculture ; Electrodes ; Graphite ; Plants ; Seawater ; Soil ; Zinc

The trace toxic metal copper was assayed using mercury immobilized on a carbon nanotube electrode (MCW), with a graphite counter and a reference electrode. In this study, a macro-scale convection motor was interfaced with a MCW three-electrode system, in which a handmade MCW was optimized using cyclic-and square-wave stripping voltammetry. An analytical electrolyte for tap water was used instead of an expensive acid or base ionic solution. Under these conditions, optimum parameters were 0.09 V amplitude, 40 Hz frequency, 0.01 V incremental potential, and a 60-s accumulation time. A diagnostic working curve was obtained from 50.0 to 350 microg/L. At a constant Cu(II) concentration of 10.0 microg/L, the statistical relative standard deviation was 1.78% (RSD, n = 15), the analytical accumulation time was only 60 s, and the analytical detection limit approached 4.6 microg/L (signal/noise = 3). The results were applied to non-treated drinking water. The content of the analyzed copper using 9.0 and 4.0 microg/L standards were 8.68 microg/L and 3.96 microg/L; statistical values R2 = 0.9987 and R2 = 0.9534, respectively. This method is applicable to biological diagnostics or food surveys.
Convection ; Copper ; Diagnosis ; Drinking Water* ; Drinking* ; Electrodes ; Graphite ; Limit of Detection ; Metals* ; Nanotubes, Carbon ; Organothiophosphorus Compounds ; Reference Standards ; Drinking Water

Trace uranium detection measurement was performed using DNA immobilized on a graphite pencil electrode (DGE). The developed probe was connected to the portable handheld voltammetric systems used for seawater analysis. The sensitive voltammogram was obtained within only 30 s accumulation time, and the anodic stripping working range was attained at 100~800 microg/l U and 10~50 microg/l. The statistic relative standard deviation of 30.0 mg/l with the 15th stripping was 0.2115. Here, toxicological and analytical application was performed in the seawater survey in a contaminated power plant controlling water. The results were found to be applicable for real-time toxicological assay for trace control.
DNA ; Electrodes ; Graphite ; Power Plants ; Seawater ; Uranium ; Seawater