Application of the Bifunctional Switch-Type Cryptand Ion Chromatographic Stationary Phase for Ion Separation

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Fullerene(C60)-dibenzo-16-crown-5-oxyacetic acid (DBI6C5-OCH2-COOC60) was prepared and applied as the coating material on piezoelectric quartz crystals for detection of various metal ions and polar/nonpolar organic molecules. The C60-crown ether-coated piezoelectric crystal sensor with a home-made computer inter face for signal acquisition and data processing was applied as an ion Chromatographie (IC) detector for various metal ions, e.g., alkali metal, alkaline earth metal and transition-metal ions. The piezoelectric detector exhib ited quite good sensitivity of 10 4 ~ 10 6 Hz/M and good detection limit of 10" 3 ~ 10" 4 M for these metal ions. The C60-crown ether piezoelectric detector compared well with the commercial conductivity detector convention ally used for metal ions. The ionic size and ionic charge seemed to have significant effect on the frequency re sponse of the piezoelectric detector. The C60-crown ether coated piezoelectric crystal sensor was also em ployed as a high performance liquid Chromatographie (HPLC) detector for various polar organic molecules with frequency responses in the order: amines > carboxylic acids > alcohols > ketones. Furthermore, nonpolar organic molecules, e.g., n-hexane, 1-hexene and 1-hexyne, were also detected with this piezoelectric crystal de tector. The frequency responses of the piezoelectric crystal detector for these nonpolar organic molecules were in the following order: alkynes » alkenes > alkanes. The effects of solvents and flow rate on the frequency re sponses of the piezoelectric crystal detector were investigated. The C60-crown ether coated piezoelectric crys tal detector also showed short response time (< 1 min.) and good reproducibility.

Section: Resultsmentioning

confidence: 99%

“…5 " 6 Because of their selectivity, crown ethers can po tentially be applied as coating adsorbents onto piezoelectric crystal surfaces to adsorb and detect metal ions and polar or ganic molecules in solutions. Piezoelectric crystals, e.g., quartz and PLZT (Pb,La,Zr,TiOx), are well known to be sensi tive to pressure on their surfaces.…”

Section: Introductionmentioning

confidence: 99%

Fullerene‐Crown Ether Coated Piezoelectric Crystal Liquid Chromatographic Detector for Metal Ions and Polar/Nonpolar Organic Molecules

Hung¹,

Shih²

2000

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Application of Cryptand/Polystyrene Drift‐Type Phase Transfer Catalysts for Reduction of Ketones

Shih

1999

A drift-type phase transfer catalyst, cryptand-22, adsorbed on poly(styrene/diviny benzene)-sulfonic resin was prepared and applied to catalyze the reduction of ketones, e.g,, acetophenone, benzophenone and benzaldehyde with NaSH, as a reducing agent, Before the reaction, cryptand-22 was adsorbed on the SUIfonic resin wilh ion-pairing, resin-S03-'NH-cryptand-22, The ion-pairs can be destroyed by adjusting the basicity of the reaction solution with NaOH and h e cryptand can be released from the resin into the reaction solution as a homogeneous catalyst during the reaction period. After the reaction, tbe cryptand catalyst can be readsorbed on the resin by adjusting the acidity of the solution with HCI and can be readily recovered by filtration like a heterogeneous catalyst. The draft-type cryptand catalyst exhibited better catalytic ability than some common crown ethers, e.g., 15-crown-5, benzo-15-crown-5, 12-crown-4 and dibenzo-18-crown-6 for the reduction of acetophenone wilh NaBH,. Effects of solvents, pH of solutions, concenuation of the catalyst, reducing agents and resin properly on the reduction of ketones were investigated and discussed.The reaction mechanism of the cryptand catalyzed reduction was also studied.

Piezoelectric Crystal Membrane Chemical Sensors Based on Fullerene and Macrocyclic Polyethers

Shih¹

2000

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Various reusable and sensitive piezoelectric (PZ) quartz crystal membrane sensors with home‐made computer interfaces for signal acquisition and data processing were developed to detect organic/inorganic vapors and organic/inorganic/biologic species in solutions, respectively. Fullerene(C60), fullerene derivatives and artificial macrocyclic polyethers, e.g., crown ethers and cryptands, were synthesized and applied as coating materials on quartz crystals of the PZ crystal sensors. The oscillating frequency of the quartz crystal decreased due to the adsorption of organic or inorganic species onto coating material molecules on the crystal surface. The crown ether‐coated PZ crystal gas detector exhibited high sensitivity with a frequency shift range of 10–340 Hz/(mg/L) for polar organic gases, a short response time (< 2.0 min.), good selectivity, and good reproducibility. The Ag(I)/crptand22 and Ru(III) / crptand22 coated PZ gas detectors were also prepared for nonpolar organic vapors, e.g., alkynes and alkenes. The frequency shifts of the nonpolar PZ sensors were in the order: alkynes > alkenes > alkanes. A Ti(IV)/Cryptand22‐coated PZ crystal sensor was also developed to detect the inorganic air pollutants, e.g., CO and NO2. A piezoelectric gas sensor for both polar/nonpolar organic vapors based on C60‐cryptand22 was also prepared. The cryptand22‐coated PZ gas sensor was also employed as a GC detector for organic molecules. The cryptand22‐coated piezoelectric GC detectors compared well with the commercial thermal conductivity detector (TCD). The interaction between fullerene C60 and organic molecules was studied with a fullerene coated PZ gas detector. A multi‐channel PZ organic gas detector with PCA(Principal Component Analysis) and BPN (Back Propagation Neural) analysis methods was developed. Various liquid piezoelectric crystal sensors based on long‐chain macrocyclic polyethers, e.g., C10H21‐dibenzo‐16‐crown‐5, C18H37‐benzo‐15‐crown‐5, (C17CO)2‐cyptand22 and fullerene derivatives, e.g., C60‐NH‐cryptand22 and dibenzo‐16‐crown‐5‐C60, were also developed as HPLC detectors for metal ions, anions, and various organic compounds in solutions. The sensitive and highly selective PZ bio‐sensors based on enzymes, polyvinylaldehyde, polycinnaldehyde‐C60 and C60‐cryptand22 were developed to detect various biologic species, e.g., proteins, glucose, and urea. A quite sensitive EQCM (Electrochemical Quartz Crystal Micro‐balance) detection system was also developed for detection of trace heavy metal ions.