A bonded polyoxyethylene phase for gas and liquid chromatography

1986 ◽  
Vol 64 (3) ◽  
pp. 470-476 ◽  
Author(s):  
Palitha P. Wickramanayake ◽  
Walter A. Aue
Keyword(s):  
Liquid Chromatography ◽  
Silica Gel ◽  
High Efficiency ◽  
Gel Permeation Chromatography ◽  
Plate Height ◽  
Bonded Phases ◽  
Elution Pattern ◽  
Gas And Liquid Chromatography ◽  
Unmodified Silica ◽  
New Phase

Bonded phases were produced by reacting 2,4,7,9-tetramethyl-5-decyne-4,7-bis(polyethyleneoxide 30 mol) ether (Surf[Formula: see text]nol® 485) with silicic supports of high and low surface area. There is circumstantial evidence (a) that the nonextractable layer is held by multiple hydrogen bonding and (b) that the synthesis of these packings involves a reaction at the crosslinking site of the surfactant. The bonded phases, with layer thicknesses between 10 and 30 Å, were tested with three chromatographic techniques. In gas–solid chromatography, the phase proved well deactivated and yielded a reduced plate height of 2.5 (using a silica gel support). In gel permeation chromatography, polyethyleneglycols eluted within the mobile-phase volume. In liquid–solid (normal-phase adsorption) chromatography, the elution pattern differed significantly from that of unmodified silica gel. In each case, high-efficiency separations were obtained. The chromatographic experiments thus demonstrated the potential usefulness of the new phase for both gas and liquid chromatography. However, it was not tested in direct comparison with conventional phases nor was its utility established by subjecting it to routine analytical use.

Multi-alkylated Polynuclear Aromatic Hydrocarbons of Tobacco Smoke: Separation and Identification

1978 ◽  
Vol 9 (4) ◽  
Author(s):  
M. E. Snook ◽  
R. F. Severson ◽  
R. F. Arrendale ◽  
H. C. Higman ◽  
O. T. Chortyk
Keyword(s):  
Liquid Chromatography ◽  
Cigarette Smoke ◽  
Aromatic Hydrocarbons ◽  
Ultra Violet ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Gel Chromatography ◽  
Cigarette Smoke Condensate ◽  
Gas And Liquid Chromatography ◽  
Silicic Acid Chromatography ◽  
Derivatives Of

AbstractThe methyl, multi-methyl, and ethyl derivatives of the polynuclear aromatic hydrocarbons (PAH) of cigarette smoke condensate (CSC) were isolated from the neutrals by silicic acid chromatography, solvent partitioning and gel chromatography. The procedure yielded a relatively pure PAH isolate amenable to further identifications. The multi-alkylated PAH were concentrated in the early gel fractions with parent and higher ring PAH found in subsequent gel fractions. It was shown that CSC is very rich in alkylated PAH, and their successful identification required extensive use of gas and liquid chromatography and ultra-violet and GC - mass spectrometric techniques. High-pressure liquid chromatography (HPLC) separated individual isomers of the alkylated PAH in complex GC peaks. PAH from indene to pentamethylchrysene were found. This report concludes our identification studies on the PAH of CSC and complements our two previous reports in this journal. Collectively, our studies have identified approximately 1000 PAH of cigarette smoke condensate and have led to the development of methods for the routine quantitation of PAH in smalI quantities of cigarette smoke condensate.

One-step Separation and Purification of Four Phenolic Acids from Stenoloma chusanum (L.) Ching by Medium-pressure Liquid Chromatography and High-speed Counter-current Chromatography

2019 ◽  
Vol 9 (2) ◽  
pp. 138-143
Author(s):  
Tianyun Li ◽  
Xiling Dai ◽  
Yichen Li ◽  
Guozheng Huang ◽  
Jianguo Cao
Keyword(s):  
Natural Products ◽  
Liquid Chromatography ◽  
Phenolic Acids ◽  
High Speed ◽  
High Efficiency ◽  
Total Phenolic ◽  
Medium Pressure ◽  
Medium Pressure Liquid Chromatography ◽  
One Step ◽  
Counter Current

Background:Stenoloma chusanum (L.) Ching is a Chinese traditional medicinal fern with high total flavonoid and total phenolic content. Traditionally, phenolic compounds were separated by using column chromatography, which is relatively inefficient. </P><P> Objective: This study aims to use an efficient method to separate natural products from S. chusanum by Medium-Pressure Liquid Chromatography (MPLC) and High-Speed Counter-Current Chromatography (HSCCC).Methods:In the present research, firstly, a sample (2.5 g) from the dichloromethane extract of S. chusanum was separated by MPLC. Next, fraction P5 was purified by HSCCC with a two-phase solvent system composed of hexane-ethyl acetate-methanol-water (HEMWat) at a volume ratio of 2:4:1:4 (v/v/v/v). </P><P> Result: Four phenolic acids were obtained and their structures were identified by means of NMR and ESI-mass analysis. They were identified as: 1) protocatechuic acid (34 mg, purity 90.1%), 2) syringic acid (66 mg, purity 99.0%), 3) p-hydroxybenzoic acid (5 mg, purity 91.2%) and 4) vanillic acid (6 mg, purity 99.3%).Conclusion:The combination of MPLC and HSCCC is a high-efficiency separation method for natural products. This is the first report with regard to the separation of four phenolic acids in one step by MPLC and HSCCC from S. chusanum (L.) Ching.

scholarly journals Resistance to Growth of Molds for Wood Modified with Hydrophobic Hybrid Silica Gel Containing Copper Amine Complexes

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 577
Author(s):  
Shaokun Hao ◽  
Chuanshuang Hu ◽  
Xiuyi Lin ◽  
Jin Gu ◽  
Hong Yun ◽  
...  
Keyword(s):  
Silica Gel ◽  
High Efficiency ◽  
Copper Chloride ◽  
Sol Gel ◽  
Untreated Wood ◽  
Populus Tomentosa ◽  
Amine Complexes ◽  
Hybrid Silica ◽  
Sol Gel Process ◽  
Copper Amine

Complexation copper with amine provides an effective strategy for fixation copper in wood, while hydrophobic modification improves the dimensional stability of wood. Thus, a combination of complexation and hydrophobization is expected to enhance the efficiency of copper-based biocides. In this study, hydrophobic hybrid silica gel containing copper amine complexes (MACu) was prepared through an in situ sol-gel process in wood using methyltriethoxysilane (MTES), 3-amino-propyltriethoxysilane (APTES), and copper chloride. The resistance to growth of molds for MACu modified wood (Populus tomentosa) was measured according to ASTM D3273-16. A leaching resistance test was carried out in accordance with AWPA E11-16. The results showed that only Aspergillus niger covered the surface of untreated wood blocks and no mold grew on the MACu surface even after the leaching test. MACu xerogel and MACu wood were further characterized by SEM-EDS, FTIR, and XPS. A possible schematic diagram of the reaction mechanism was proposed to explain the high-efficiency anti-mold performance of MACu wood.

Carboxylated cyclofructan 6 as a hydrolytically stable high efficiency stationary phase for hydrophilic interaction liquid chromatography and mixed mode separations

2016 ◽  
Vol 8 (31) ◽  
pp. 6038-6045 ◽  
Author(s):  
Yadi Wang ◽  
M. Farooq Wahab ◽  
Zachary S. Breitbach ◽  
Daniel W. Armstrong
Keyword(s):  
Liquid Chromatography ◽  
Benzoic Acid ◽  
Stationary Phase ◽  
Mixed Mode ◽  
High Efficiency ◽  
Stationary Phases ◽  
Hydrophilic Interaction Liquid Chromatography ◽  
Hydrophilic Interaction

Stationary phases composed of native cyclofructan 6 (CF6) and benzoic acid modified CF6 were synthesized and evaluated for hydrophilic interaction liquid chromatography (HILIC).

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