抄録
Agricultural chemicals have various toxicities and would have caused parts of accidental water pollutions. Recently, waterworks act was amended. One hundred and two agricultural chemicals were added as complementary items to monitor tap water and environmental water. Stir bar sorptive extraction (SBSE) is recognized as a useful and prompt screening method of analysis. In this study, the effect of analytical condition and n-octanol/water partition coefficient (Kow) of agricultural chemicals on the extraction recovery by stir bar of polydimethylsiloxane (PDMS) was investigated to enhance the accuracy of the SBSE method.
PDMS/water partition coefficient (KPDMS W) that was the ratio of concentration of agricultural chemicals in PDMS to that in water sample in equilibrium was calculated. The PDMS segments activities increases with increasing temperature to contain agricultural chemicals. On the other hand, water solubility of agricultural chemicals increases with increasing temperature. In the range of 5 °C to 40 °C, Log (KPDMS W) increases with increasing temperature up to 25 °C and the maximum Log (KPDMS W) is reached at 25°C, thereafter, it decreased. Additionally, the determination coefficient (R2) of Log(KPDMS W) and Log (Kow) shows the maximum value at 25 °C. Water temperature, Log (Kow) and concentration of agricultural chemicals in water sample would have effected on recoveries in the SBSE method. It suppressed these effects and enhanced the accuracy of the SBSE method that the solutions to make calibration curves were added NaCl and extracted by SBSE method as well as sample solutions.
