The effect of temperature on the adsorption/desorption of ammonia from the air mixture on the surface of commercial binary
V/Al and ternary Pd/V/Al, V(0.65 wt.%) /W(6.73 wt.%) /Ti and V(1.8 wt.%) /W(7.3 wt.%) /Ti de-NOx catalysts has been investigated by temperature-programmed desorption (TPD) method. The ability of the commercial catalysts
to adsorb ammonia in the most stable surface species was shown to correlate well with their suppression of the NH3 oxidation. 相似文献
A sensitive, selective, and reproducible in-tube solid-phase microextraction and liquid chromatographic (in-tube SPME/LC-UV) method for determination of lidocaine and its metabolite monoethylglycinexylidide (MEGX) in human plasma has been developed, validated, and further applied to pharmacokinetic study in pregnant women with gestational diabetes mellitus (GDM) subjected to epidural anesthesia. Important factors in the optimization of in-tube SPME performance are discussed, including the draw/eject sample volume, draw/eject cycle number, draw/eject flow rate, sample pH, and influence of plasma proteins. The limits of quantification of the in-tube SPME/LC method were 50 ng/mL for both metabolite and lidocaine. The interday and intraday precision had coefficients of variation lower than 8%, and accuracy ranged from 95 to 117%. The response of the in-tube SPME/LC method for analytes was linear over a dynamic range from 50 to 5000 ng/mL, with correlation coefficients higher than 0.9976. The developed in-tube SPME/LC method was successfully used to analyze lidocaine and its metabolite in plasma samples from pregnant women with GDM subjected to epidural anesthesia for pharmacokinetic study. 相似文献
Thermal analysis combined with evolved gas analysis has been used for some time. Thermogravimetry (TG) coupled with Fourier
transform infrared (FTIR) spectroscopy(TG/FTIR), Thermogravimetry (TG) coupled with mass spectrometry (TG/MS), and Thermogravimetry
(TG) coupled with GC/MS offers structural identification of compounds evolving during thermal processes. These evolved gas
analysis (EGA) techniques allow to evaluate the chemical pathway of the degradation reaction by determining the decomposition
products. In this paper the TG/FTIR, TG/MS, and Pyrolysis/GC-MS systems will be described and their applications in the study
of several materials will be discussed, including the analysis of the degradation mechanisms of organically modified clays,
polymers, and coal blends.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
An ultra-sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the analysis of oral contraceptive ethinyl estradiol (EE) was developed and validated over the curve range of 2.5-500 pg/mL using 1 mL of human plasma sample. Ethinyl estradiol and the internal standard, ethinyl estradiol tetra-deuterated (EE-d4), were extracted from the plasma matrix with methyl t-butyl ether, derivatized with dansyl chloride and then back-extracted into hexane. The hexane phase was evaporated to dryness, reconstituted and injected onto the LC/MS/MS system. The chromatographic separation was achieved on a Luna C(18) column (50 x 2 mm, 5 micro m) with an isocratic mobile phase of 20:80 (v/v) water:acetonitrile with 1% formic acid. The offline derivatization procedure introduced the easily ionizable tertiary amine function group to EE. This greatly improved analyte sensitivity in electrospray ionization and enabled us to achieve the desired lower limit of quantitation at 2.5 pg/mL. This high sensitivity method can be used for therapeutic drug monitoring or supporting bio-equivalence and drug-drug interaction studies in human subjects. 相似文献