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排序方式: 共有663条查询结果,搜索用时 15 毫秒
1.
R W Milne R L Nation G D Reynolds A A Somogyi J T Van Crugten 《Journal of chromatography. A》1991,565(1-2):457-464
Improvements to previously reported methods for the determination of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in human plasma are described. The improved methods involve the use of a solid-phase extraction cartridge and a chromatographic system which uses paired-ion reversed-phase high-performance liquid chromatography with a radially compressed column. Only one cartridge is used to prepare each sample for chromatography and each cartridge may be used for at least fourteen 1-ml plasma samples. The recovery is greater than 85%. The improvements to the method of sample pretreatment and in the chromatographic conditions have allowed determination of morphine, M3G and M6G in human plasma down to 13.3 nmol/l (coefficient of variation = 9.3%), 108 nmol/l (6.6%) and 41 nmol/l (6.7%), respectively, using ultraviolet detection alone. It was shown that all three compounds were stable in plasma for up to 101 weeks when stored at -20 degrees C. 相似文献
2.
K. Reynolds É. Murray A. O’Riordan G. Redmond 《Applied Physics A: Materials Science & Processing》2006,82(1):23-26
Capillary interaction-based self-assembly of block-shaped mesoscale components into an electrically interconnected 1-D tetramer is reported. Low melting point solder droplets, selectively patterned on the faces of the blocks, were employed to drive the sequential alignment, registration, linking and electrical interconnection of each block. The solder patterns were designed so that successful assembly would only occur when the solder patterns on one block face were correctly aligned with those on the face of an adjacent block. For assembly, the blocks were agitated in a flask containing KBr solution. At 60 °C the solder was molten, and collisions between blocks enabled the solder menisci to easily interact. To minimize interfacial free energy, the menisci coalesced and quickly drove the interacting blocks to form a stable, registered and aligned assembly. When agitation was terminated and the solution cooled, the self-aligned, linear tetrameric arrangement of blocks was permanently captured by solder solidification, a process that provided good mechanical bonding and electrical interconnection between each block. PACS 81.16.Dn; 68.03.Cd; 85.40.-e 相似文献
3.
Studies of the application of an 8-hydroxyquinoline extraction and of a zinc oxide “collection” procedure for the separation of trace amounts of indium from zinc alloys are described and discussed. A combination of radio-chemical and polarographic determination were employed for this work. A polarographic method for the determination of indium in zinc and in zinc alloys of low aluminium content is presented 相似文献
4.
Johnny D. Reynolds Kelsey D. Cook 《Journal of the American Society for Mass Spectrometry》1990,1(3):233-237
The abundance of ion pairs (CA+) relative to that of doubly charged ions (C2+) in electrohydrodynamic (EH) mass spectra of a series of anions with a common dication in glycerol was found to increase in the order acetate < nitrite < chloride < bromide ≈ nitrate < iodide < perchlorate. Correlation with enthalpies of hydration for the anions suggests that this trend reflects the solution chemistry of ion association. These spectra also reveal that solvation rather than interactions with the extracting field is more important in determining the overall EH mass spectrometric sensitivity to doubly charged ions. Therefore, the use of anions that promote more extensive ion pairing enhances the overall sensitivity to multiply charged ions that otherwise interact strongly with the solvent, but reduces sensitivity to singly charged ions. These observations hold in fast atom bombardment mass spectrometry, surviving the invasive effects of the primary beam. 相似文献
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7.
1,3,5-Trisubstituted hexahy drotriazines react with hydrogen chloride in the presence of anhydrous solvents to form useful intermediates for the introduction of the RNHCH2- group into compounds which undergo the Mannich reaction. The effectiveness of the new aminomethyl-ating agent has been demonstrated by the preparation of secondary aminomethyl sulfide hydro-chlorides. 相似文献
8.
Hodgson DM Kirton EH Miles SM Norsikian SL Reynolds NJ Coote SJ 《Organic & biomolecular chemistry》2005,3(10):1893-1904
Organolithium-induced deprotonation of terminal epoxides in the presence of appropriate diamine ligands allows trapping with a range of electrophiles, yielding functionalised di- and tri-substituted epoxides in good yields and with control of stereochemistry at the epoxide. 相似文献
9.
Köse ME Crutchley RJ Derosa MC Ananthakrishnan N Reynolds JR Schanze KS 《Langmuir : the ACS journal of surfaces and colloids》2005,21(18):8255-8262
Polymer films consisting of a linear poly(dimethylsiloxane) end-functionalized with a luminescent Ir(III) complex (Ir-PDMS), blended with polystyrene (PS), function as optical oxygen sensors. The sensor response arises by quenching of the luminescence from the Ir(III) chromophore by oxygen that permeates into the polymer film. The morphology and luminescence oxygen sensor properties of blend films consisting of Ir-PDMS and PS have been characterized by fluorescence microscopy, atomic force microscopy, and scanning electron microscopy. The investigations demonstrate that microscale phase segregation occurs in the films. In blends that contain a relatively small amount of Ir-PDMS in PS (ca. 10 wt %), the Ir-PDMS exists as circular domains, with diameters ranging from 2 to 5 mum, surrounded by the majority PS phase. For larger weight fractions of Ir-PDMS in the blends, the film morphology becomes bicontinuous. A novel epifluorescence microscopy method is applied that allows the construction of Stern-Volmer quenching images that quantify the oxygen sensor response of the blend films with micrometer spatial resolution. These images provide a map of the oxygen permeability of the polymer blend films with a spatial resolution of ca. 1 mum. The results of this investigation show that the micrometer-sized Ir-PMDS domains display a 2-3-fold higher oxygen sensor response compared to the surrounding PS matrix. This result is consistent with the fact that PDMS is considerably more gas permeable compared to PS. The relationship of the microscale morphology of the blends to their performance as macroscale optical oxygen sensors is discussed. 相似文献
10.
Aboelella NW Lewis EA Reynolds AM Brennessel WW Cramer CJ Tolman WB 《Journal of the American Chemical Society》2002,124(36):10660-10661
The X-ray structure of a 1:1 Cu/O(2) adduct revealed side-on (eta(2)) O(2) coordination. Density functional calculations corroborated the structure, indicated a significant contribution of a Cu(III)-(O(2)(2-)) resonance form, and provided insights into the key bonding interactions. Reaction of a 1:1 adduct supported by a slightly different beta-diketiminate ligand with Cu(I) reagents resulted in the formation of novel asymmetric bis(mu-oxo) complexes that were identified by EPR, UV-vis, and Raman spectroscopy, as well as by an X-ray structure in one instance. 相似文献