Inorganic/organic mesoporous silica as a novel fiber coating of solid-phase microextraction.

Mesoporous materials were employed as fast, sensitive and efficient fiber coatings of solid-phase microextraction (SPME) for the first time. Three micrometer as-synthesized C(16)-MCM-41 particles were immobilized onto stainless steel wire with 100mum coating thickness. In combination with high performance liquid chromatography (HPLC), extraction efficiency and selectivity of C(16)-MCM-41 were investigated using aromatic hydrocarbons. Effect of extraction and desorption time, extraction temperature, stirring rate and ionic strength on extraction efficiency were examined. Aanalytical merits of SPME with C(16)-MCM-41 coating were evaluated. The chromatographic peak area is proportional to the concentration of anthracene in the range 0.5-150mugl(-1). The limit of detection was 0.05mugl(-1) (S/N=3) and the relative standard deviation (R.S.D.) was 0.033%.

[Comparative study of room-temperature phosphorescence of 1-bromonaphthalene induced by synergetic effect of nonionic surfactants and beta-cyclodextrin].

Room-temperature phosphorescence of 1-BrN induced by a combination of OPE-10 and Triton X-100 with beta-CD was comparatively studied. In terms of molecular size and dimensions of beta-CD, the octyl group and phenyl group of OPE-10 and Triton X-100 were incorporated into the cavity of beta-CD and the complexes with the stoichiometry of 1:1 were formed. The removal of water molecules inside the cavity results in a greater apolar interior. By enhanced hydrophobic interaction, the cavity occupied by OPE-10 and Triton X-100 is able to further capture another 1-BrN and form close packing 1:1:1 ternary inclusion complexes with apparent stability constant of 1.09 x 10(5) and 4.47 x 10(5) L2 x mol(-2), respectively. 1-BrN shows bright phosphorescence at room temperature due to the greater rigidity in the limited space and the favorable microenvironment shielding from external quenchers and quenching effect on the fluorescence of the phenyl group of OPE-10 and Triton X-100 within the same cavity. In the case of Triton X-100, the larger tert-octyl group better shields off external quenchers such as dissolved oxygen and iodide ion. Energy transfer from the excited phenyl group of Triton X-100 to adjacent 1-BrN acceptor was observed.

[Study of the acupuncture effect on monoamine transmitters in rabbit plasma and brain tissue by high performance liquid chromatography with electrochemical detection].

A rapid and simple method for the study of the acupuncture effect on monoamine transmitters and related compounds in rabbit plasma and brain tissue by high performance liquid chromatography with electrochemical detection was developed. An ODS column was selected as the separation column at 25 degrees C, and pH 4.50, 0.02 mol/L of trisodium citrate-0.05 mol/L sodium phosphate dibasic to methanol (95:5, volume ratio) without ion-pair at a flow rate of 1.0 mL/min. Four compounds, epinephrine (E), norepinephrine (NE), dopamine (DA) and 5-hydroxytryptamine (5-HT), were simultaneously separated and determined under the above conditions. Twenty rabbits were investigated after the acupuncture action upon the central neurotransmitters. The sufficient data showed that acupuncture could significantly affect the activities of the neurotransmitters including E, NE, DA and 5-HT, and the changed functions of the neurotransmitter systems induced by acupuncture not only lead to the neurotransmitter content increase both in brain and plasma but also cause the increase of rabbit breed ability. The results show that the method is very simple and fast. The method is valuable not only for clinical diagnosis but also for research work.