Gradients of n‐heptane and acetonitrile in silver‐ion high‐performance liquid chromatography analyses of cis and trans bonds in lipids

Elfman‐Börjesson, Inger; Hark, Sander van den; Härröd, Magnus

doi:10.1007/s11746-997-0043-y

Cited by 10 publications

(5 citation statements)

References 12 publications

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“…Samples of the reaction product were taken from the high-pressure section (see A) and analyzed on a silverion high-pressure liquid chromatograph (HPLC). 14 In an empty HPLC tube, a fixed-bed reactor (see reactor 2 in Figure 2) was created with catalyst particles in different fractions, between 32 and 500 µm. A copperbased catalyst (Cu-1985 T; Engelhard, De Meern, The Netherlands) was used, if not specified else.…”

Section: Methodsmentioning

confidence: 99%

“…This expansion valve consisted of a needle-type valve (Autoclave Engineers, Erie, PA). Samples of the reaction product were taken from the high-pressure section (see A) and analyzed on a silver-ion high-pressure liquid chromatograph (HPLC) 2 Flow sheet of the lab-scale continuous supercritical hydrogenation reactor [reactor 1 = saturation of FAME, Pd catalyst, reactor 2 = formation of FOH, Cu catalysts, P in = system pressure (inlet pressure), P out = pressure after the reactor, A = sampling point, R = fluid expansion valve, F = flowmeter]. …”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Fixed-Bed Hydrogenation at Supercritical Conditions To Form Fatty Alcohols: The Dramatic Effects Caused by Phase Transitions in the Reactor

Hark

Härröd

2001

Ind. Eng. Chem. Res.

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Natural fatty alcohols are one of the major oleochemicals and can be produced by catalytic hydrogenation of fatty acid methyl esters. In the commercial multiphase process, the hydrogen availability to the solid catalyst limits the reaction rate. By adding propane to the reaction mixture, we can utilize the unique properties of supercritical fluids, properties between those of gases and liquids. Using propane, a substantially homogeneous supercritical phase is created, whereby hydrogen has complete access to the solid catalyst. At high substrate concentrations, a rapid fall of the reaction rate was observed, and the benefits of the propane addition were completely lost. This fall depends on a split of the supercritical reaction mixture into two phases (a substrate-rich and a hydrogen-rich phase). If this phase split occurred using small catalyst particles (e32 µm), the pressure drop over the catalyst bed increased sharply because the formed liquid droplets blocked the void space in the porous catalyst bed. These two phenomena were used to deduce the product and substrate solubility in the reaction mixture. The product showed the most unfavorable solubility which increased with higher pressure. Under our process conditions (150 bar, 280 °C, and 11 mol % hydrogen), a single phase was observed up to 2 mol % (i.e., 15% by mass) product. Besides the minimum pressure in the catalyst bed, substrate transport limitation could be shown to be an important factor in process optimization. Therefore, egg-shell catalysts or fine catalyst particles (100-300 µm) should preferably be used in the continuous supercritical reactors.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Fixed-Bed Hydrogenation at Supercritical Conditions To Form Fatty Alcohols: The Dramatic Effects Caused by Phase Transitions in the Reactor

Hark

Härröd

2001

Ind. Eng. Chem. Res.

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“…370 cis and trans Isomers of fatty acid methyl esters, fatty alcohols and triacylglycerols were separated on a silver-ion HPLC column using gradients of n-heptane and acetonitrile as eluent. 371 The mechanistic aspects of fatty acid retention in silver-ion HPLC have been described. 372 An industrial HPLC purification method for the isolation of docosahexaenoic acid ethyl ester and docosapentaenoic acid ethyl ester from singlecell oil in 99+% purity has been developed.…”

Section: High Pressure Liquid Chromatographymentioning

confidence: 99%

Fatty acids, fatty acid analogues and their derivatives

Jie¹,

Pasha²

1998

Nat. Prod. Rep.

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“…The advantages of this isocratic solvent system are the lack of solvent equilibration between the runs and the use of nonchlorinated solvents, but in complicated TAG analysis, this system may not be sufficient. Elfman-Bo ¨rjesson et al 35 presented analysis of cis and trans isomers of FAME, mixtures of FAMEs and fatty alcohols, and TAGs with gradients of n-heptane and acetonitrile in the Ag-HPLC system. Fe ´vrier et al 36 used one commercial silver ion column and mobile phases containing n-hexane, 2-propanol, ethyl acetate, and acetonitrile to separate positional isomers of TAGs and DAGs.…”

mentioning

confidence: 99%

Regioisomeric Structure Determination of α- and γ-Linolenoyldilinoleoylglycerol in Blackcurrant Seed Oil by Silver Ion High-Performance Liquid Chromatography and Mass Spectrometry

et al. 2008

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Gamma-linolenic acid (Gla) and oils containing Gla have evident positive effects on a variety of disorders, and therefore, the structure of triacylglycerols (TAGs) containing Gla is of special interest. The regioisomeric structures of TAGs 18:3(n-3)/18:2/18:2 (Ala/L/L) and 18:3(n-6)/18:2/18:2 (Gla/L/L) in blackcurrant seed oil were determined by Ag-HPLC/APCI-MS and Ag-HPLC/ESI-MS/MS techniques. In the latter, silver ion adducts were prepared by adding silver nitrate to the postcolumn flow. A new Ag-HPLC solvent system containing nonchlorinated solvents for the separation of Gla- and Ala-containing TAGs is introduced. Ag-HPLC separation of Ala/L/L and Gla/L/L was sufficient and regioisomers sn-LnLL + sn-LLLn and sn-LLnL (Ln, linolenic acid) could be differentiated well with the MS methods used. No discrimination was made between the sn-1 and sn-3 positions. The results show that the methods used are suitable to discriminate and determine the regioisomeric structure of TAGs. The regioisomeric structure of TAG with the fatty acid combination Gla/L/L in blackcurrant seed oil was considered to be practically random (32.7-37.8% of sn-LGlaL). In the fatty acid combination Ala/L/L, the regioisomeric structure is nonrandom (7.3-12.1% of sn-LAlaL) with Ala preferentially in a primary position. It can be concluded that the positional distribution of Ala and Gla is different in Ln/L/L TAGs of blackcurrant seed oil.

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Gradients of n‐heptane and acetonitrile in silver‐ion high‐performance liquid chromatography analyses of cis and trans bonds in lipids

Cited by 10 publications

References 12 publications

Fixed-Bed Hydrogenation at Supercritical Conditions To Form Fatty Alcohols: The Dramatic Effects Caused by Phase Transitions in the Reactor

Fixed-Bed Hydrogenation at Supercritical Conditions To Form Fatty Alcohols: The Dramatic Effects Caused by Phase Transitions in the Reactor

Fatty acids, fatty acid analogues and their derivatives

Regioisomeric Structure Determination of α- and γ-Linolenoyldilinoleoylglycerol in Blackcurrant Seed Oil by Silver Ion High-Performance Liquid Chromatography and Mass Spectrometry

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