| 摘要 |
Addition of green tea shows an effect on removal of lead ions through the reduction in conductivity using a result of conductivity measurement, whereas ionized water in the green tea can affect the result of the measurement, thereby setting a solution to be compared to be 500 ppm and 75 ml in volume so as to be equal to a standard solution. As the concentration of the lead standard solution can be lower than the concentration of the solution to be compared, the conductivity of the solution is adjusted to be increased by 500 ppm or the increased conductivity of the green tea using KNO_3 containing ions while watching an electrical conductivity meter. Then, 1 ml of the 20000 ppm lead standard solution is instilled into both sides and the time course change of the conductivity is observed (the conductivity increases up to about 1500 ppm). As the conductivity may be increased by releasing ions from a sample depending on samples, a change in the conductivity of the samples should be examined in advance. In addition, as the temperature has to be increased by a certain temperature to allow heavy metals to interact with a substance having an effect on the removal of the heavy metals, a change in the conductivity after raising the temperature should be observed. The result of changes in the conductivity of see mustard, garlic, green tea, and the lead standard solution measured by the electrical conductivity meter showed the see mustard and the green tea leaves absorbed lead ions, whereas the conductivity of the garlic increased. However, an increase in the conductivity of a substance like garlic may be due to release of ionic matter from the substance by a rise in the temperature. Thus, the concentration of lead can be calculated by comparing a change in color of unique yellow precipitation, which is formed by putting an excess KI solution interacting lead, with the lead concentration to precisely detect the lead in the ionized solution. |
