- 作者: 宋美芳,施正雄
- 作者服務機構: Department of Chemistry, National Taiwan Normal University, Taipei 116, Taiwan, R.O.C.
- 中文摘要: A water insoluble long-chain crown ether alkyl (C18)-benzo-15-crown-5 was synthesized and applied as a coating material on quartz crystal membranes of a liquid flow piezoelectric crystal sensor. The oscillating crown ether-coated piezoelectric (PZ) crystal with a home-made computer interface was prepared as a liquid chromatographic (LC) detector for organic species and metal ions in aqueous solutions. The oscillating frequency of the quartz crystal decreased due to the adsorption of organic molecules or metal ions on crown ether molecules. Effects of functional group, molar mass, steric hindrance, and polarity of organic molecules on frequency responses of the crown ether coated PZ crystal detector were investigated. The frequency responses of the crown ether coated PZ crystal detector for various molecules were in the order: amines > carboxylic acids > alcohols > ketones. The crown ether PZ detector also exhibited good sensitivity for some heavy metal ions and the frequency shifts were in the order: Cr3+ >> Pb2+ > Co2+ > Cd2+ > Ni2+ > Cu2+. The crown ether coated piezoelectric crystal LC detector demonstrated low detection limits for various polar organic molecules, e.g., 6.0 ’ 10-5 M for propylamine, and metal ions, e.g., 2.9 ’ 10-5 M (1.8 ppm) for Cu2+; the crown ether PZ detector also gave good reproducibility when reused. A quite sensitive electrochemical quartz crystal microbalance (EQCM) detection system was also set-up for detecting trace heavy metal ions in solutions. The variation in frequency of the PZ crystal and the diffusion current were observed simultaneously after the reduction in heavy metal ions such as Cu2+ and Ni2+. The EQCM detection system exhibited fairly good sensitivity, e.g., 112 Hz/ppm for Cu2+ and a good detection limit, e.g., 0.13 ppm for Cu2+ ions. Comparison between EQCM and PZ detection systems was made and discussed.
- 英文摘要: --
- 中文關鍵字: Crown ethers; Piezoelectric liquid chromatographic detector; Organic molecules; Heavy metal ions; Electrochemical quartz crystal microbalance.
- 英文關鍵字: --