Correlation between reversed-phase retention and solute molecular surface type and area

Möckel, H. J.; Welter, G.; Melzer, H.

doi:10.1016/s0021-9673(01)94487-5

Cited by 50 publications

(10 citation statements)

References 35 publications

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“…In general, the extracted substance would increase at higher temperatures due to the increasing solubility of the substance at higher temperatures [8]. It can be happened because an increase in operating temperature will result in a decrease in surface tension and the viscosity of the solute, furthermore the extraction efficiency will increase [9]. This is consistent with the experiments which states that the increase of the extraction temperature linear to the yield of carrageenan [10].…”

Section: Effect Of Extraction Temperature On the Yield Of Carrageenansupporting

confidence: 81%

Extraction of Phytochemical Compounds from Eucheuma cottonii and Gracilaria sp using Supercritical CO₂ Followed by Subcritical Water

et al. 2018

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Extraction of phytochemical compounds (such as β-carotene, linoleic acids, carrageenan, and polyphenols) from algae Eucheuma cottonii and Gracilaria sp with supercritical CO2 followed by subcritical water has been investigated. Supercritical CO2 extraction was carried out at pressure of 25 MPa, temperature of 60°C, CO2 flowrate of 15 ml/min, and ethanol flowrate of 0.25 ml/min. To determine the content of carotenoids and linoleic acids, the extracted compounds were analyzed using a spectrophotometer UV-Vis. The residue of algae starting material was subsequently extracted by subcritical water at pressures of 3, 5, and 7 MPa, and temperatures of 120, 140, 160, and 180 °C. Carrageenan extracted by subcritical water was analyzed using Fourier Transform Infra Red (FTIR), while the total phenolic compound was analyzed with UV-vis spectrophotometer. Moreover, the antioxidant efficiency of extract was also examined by DPPH assay method. Based on the analytical result, β-carotene and linoleic acid content in Eucheuma cottonii were 209.91 and 321.025 μg/g sample, respectively. While β-carotene and linoleic acid content in Gracilaria sp were 219.99 and 286.52 μg/g sample, respectively. The optimum condition of subcritical water extraction was at 180°C and 7 MPa. At this condition, the highest TPC content in the extract from Eucheuma cottonii and Gracilaria sp were 18.51 mg GAE/g sample and 22.47 mg GAE/g sample, respectively; while the highest yield of carrageenan extracted from Eucheuma cottonii and Gracilaria sp were 61.33 and 65.54 g/100 g dried algae, respectively. At the same condition, the antioxidant efficiency was 0.513 min-1 for Eucheuma cottonii and 0,277 min-1 for Gracilaria sp. Based on the results the extraction method effectively separated non-polar and polar compounds, then increased the antioxidant efficiency of extract.

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Section: Effect Of Extraction Temperature On the Yield Of Carrageenansupporting

confidence: 81%

Extraction of Phytochemical Compounds from Eucheuma cottonii and Gracilaria sp using Supercritical CO₂ Followed by Subcritical Water

et al. 2018

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“…The rearrangement of the endo methylthio-substituent to an exo methylthio-substituent, such as displayed in the tentative structure 9, is consistent 9 with such change in surface area. The relationships between molecular surface areas of hydrocarbons and their reversed-phase retention behavior were documented by Möckel et al, 41 indicating a significant influence of molecular surface area on chromatographic retention. If indeed 9 is the product of reduction, it may be conjectured that the endo-amide group directs the diimide for endo-attack rather than the expected sterically preferred exo attack in analogy with the reported 42,43 directing effect of an acetate moiety in diimide reduction.…”

Section: Cid Ofmentioning

confidence: 85%

Neighboring amide participation in the Fenton oxidation of a sulfide to sulfoxide, vinyl sulfide and ketone relevant to oxidation of methionine thioether side chains in peptides

et al. 2016

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Oxidation of Met affects the stability of proteins, and was identified as a step in the beta amyloid-dependent pathogenesis of Alzheimer's disease. One-electron oxidation of Met is facilitated through stabilization of sulfide radical cations with electron-rich heteroatoms. The formation of such 2-center-3-electron bonds, formed between sulfide radical cations and amides, leads to pronounced product selectivity during biologically relevant oxidation conditions. Conformationally constrained methionine analogs embedded within a norbornane framework, i.e., 2,6-endo, endo-and 2,6-exo, endo-pyrrolidine amide thiomethyl bicyclo[2.2.1]heptanes

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“…This may be connected with the fact that the methyl group surface is somewhat larger than the methylene surface (34.89 and 22.67 ? 2 , respectively) [30] that effects retention increase. The mean values of this parameter are 0.562, 0.543, and 0.503 for column C18, C8, and C4, respectively, and are comparable to the literature data.…”

Section: Determination Of Log K W Valuesmentioning

confidence: 95%

The Effect of the Chain Length of Bonded Phase on Retention of Aromatic Solutes in Rp Lc With Pure Water as Mobile Phase

Kwietniewski

2010

Journal of Liquid Chromatography & Related Technologies

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& Retention factors (log k w ) in pure water were calculated for a homologous series of alkylbenzenes, PAHs, and aromatic monosubstituted derivatives for column C18, C8, and C4, using the numerical method based on the linear form of the Os´cik's equation, which were correlated with the log k w values determined by the linear extrapolation method from the log k dependence on methanol volume fraction in binary eluent. The chromatographic parameters (log k w ), being the hydrophobicity measure, were compared with the experimental partition coefficients in n-octanol=water system (log P). The author examined the contribution of the substituents (ÀCH 2 À, ÀOH, ÀCl, ÀNO 2 , and ÀCHO) in the substance retention in pure water for columns of different hydrocarbon chain length of the bonded phase. Moreover, the transfer thermodynamics of the particular functional groups from water to the stationary phase, as well as the influence of the kind of the stationary phase on the thermodynamics of this process were studied. For this purpose the standard free enthalpy (DG o ) of the functional groups transfer from water to the stationary phase and from the gas to stationary one was calculated.

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Correlation between reversed-phase retention and solute molecular surface type and area

Cited by 50 publications

References 35 publications

Extraction of Phytochemical Compounds from Eucheuma cottonii and Gracilaria sp using Supercritical CO₂ Followed by Subcritical Water

Extraction of Phytochemical Compounds from Eucheuma cottonii and Gracilaria sp using Supercritical CO₂ Followed by Subcritical Water

Neighboring amide participation in the Fenton oxidation of a sulfide to sulfoxide, vinyl sulfide and ketone relevant to oxidation of methionine thioether side chains in peptides

The Effect of the Chain Length of Bonded Phase on Retention of Aromatic Solutes in Rp Lc With Pure Water as Mobile Phase

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Correlation between reversed-phase retention and solute molecular surface type and area

Cited by 50 publications

References 35 publications

Extraction of Phytochemical Compounds from Eucheuma cottonii and Gracilaria sp using Supercritical CO2 Followed by Subcritical Water

Extraction of Phytochemical Compounds from Eucheuma cottonii and Gracilaria sp using Supercritical CO2 Followed by Subcritical Water

Neighboring amide participation in the Fenton oxidation of a sulfide to sulfoxide, vinyl sulfide and ketone relevant to oxidation of methionine thioether side chains in peptides

The Effect of the Chain Length of Bonded Phase on Retention of Aromatic Solutes in Rp Lc With Pure Water as Mobile Phase

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Product

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Extraction of Phytochemical Compounds from Eucheuma cottonii and Gracilaria sp using Supercritical CO₂ Followed by Subcritical Water

Extraction of Phytochemical Compounds from Eucheuma cottonii and Gracilaria sp using Supercritical CO₂ Followed by Subcritical Water