Variables affecting resolution of lung phospholipids in one-dimensional thin-layer chromatography.
(73/78)
Resolution of the confusion in the literature about the separation of lung phospholipids in thin-layer chromatographic systems has awaited a systematic study of the variables that potentially affect this separation. In this study I show that: incorporation of ammonium sulfate into silica gel "GHL" has a dramatic effect on separation of lung phospholipids; this effect is equally dramatic but different in activated and nonactivated gels; when it picks up moisture, ammonium sulfate-activated gel very rapidly loses its ability to resolve lecithin from phosphatidylinositol; in gel containing ammonium sulfate, small amounts of phosphatidylethanolamine are hydrolyzed to lyso-phosphatidylethanolamine. (+info)
Silica gel as transport medium for Corynebacterium diphtheriae under tropical conditions (Indonesia )
(74/78)
Silica gel was confirmed as a useful transport medium for Corynebacterium diphtheriae in the investigation of diphtheria cases in which there is no ready access to laboratory facilities. (+info)
Synthesis of oligodeoxyribonucleotides on silica gel support.
(75/78)
A rapid solid phase method of oligonucleotide synthesis based on monomeric protected nucleosides has been developed. (+info)
Silica gel: an improved support for the solid-phase phosphotriester synthesis of oligonucleotides.
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The phosphotriester method for the stepwise synthesis of deoxyoligonucleotides has been employed using HPLC-grade silica gel (Porasil B) as the solid support. The procedure results in a convenient flow-through system for the synthesis of oligomers where all the reaction steps including the zinc bromide method of detritylation are compatible with the selected support. Deoxyoligonucleotides of 25-30 nucleotides in length can be synthesized in high yields utilising stable phosphotriester intermediates. Ease of handling of the solid support allows convenient synthesis of mixed oligonucleotide sequences. (+info)
Multiresidue recovery at PPB levels of 10 nitrosamines from frankfurters by supercritical fluid extraction.
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The design of a laboratory-assembled supercritical fluid extractor is described for the efficient recovery of volatile nitrosamines from a common-cured meat product, frankfurters. The principal feature of the apparatus was a newly designed restrictor-collector interface where a commercial solid-phase extraction cartridge was directly attached to the micrometering valve. This reduced the path length between the discharge tube and the 1 g silica gel sorbent bed. The elapsed time for each 2.5 g sample extraction with supercritical CO2 was 17 min. The nitrosamines were separated and detected using a gas-chromatographic chemiluminescence (Thermal Energy Analyzer, Thermedics, Inc.; Woburn, MA) system. Recovery of 10 volatile aliphatic and alicyclic nitrosamines from frankfurters, fortified at the 20 ppb level, ranged from 84.3 to 104.8% with relative standard deviation of 2.34 to 6.13%. (+info)
Evaluation of silica gel packages for transport of Neisseria meningitidis.
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Eight Neisseria meningitidis reference strains, representing six different serogroups, were plated on 57 blood agar plates each. The growth was harvested and stored in silica gel packages at different temperatures for up to 90 days. When held at 4 degrees C, all strains were recovered after 90 days of storage. Strains held at room temperature or alternately at 4 degrees C and room temperature survived for at least 10 and 17 days, respectively. (+info)