The use of gel chromatography for the determination of sizes and relative molecular masses of proteins. Interpretation of calibration curves in terms of gel-pore-size distribution

The separation of proteins by gel-exclusion chromatography has been explained in terms of partitioning of the macromolecules within the gel by a distribution of pores of various radii. The assumption that the distribution of pore sizes is Gaussian has led to the prediction of a linear relationship between the molecular Stokes radius (RS) of the protein and the function erf-1 (1-KD), where KD is the partition coefficient [Ackers (1967) J. Biol. Chem. 242, 3237-3238]. Since careful calibrations of classical (agarose and dextran) gels and h.p.l.c. gels have shown that such a linear relationship is not verified experimentally over a wide range of native protein sizes, we have reinvestigated the model of Ackers (above reference). We show that Ackers' (above reference) derivation is not valid except for a particular Gaussian distribution of pore sizes centred at the origin. Relaxation of this restriction to allow for other types of Gaussian distributions cannot account for the non-linear calibration curves that we have obtained. Instead we show that the pore-size distribution can be calculated from the experimentally determined function KD = f(RS) and that this distribution is bimodal (non-Gaussian). One distribution is centred below 2 nm, whereas the mean value of the second one is around 6-8 nm. The minimum in this bimodal distribution corresponds, for some gels, to a region of poor resolution, which needs to be appreciated for the proper use of gel chromatography in the determination of molecular size.

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The use of gel chromatography for the determination of sizes and relative molecular masses of proteins. Interpretation of calibration curves in terms of gel-pore-size distribution

Biochemical Journal ◽

10.1042/bj2450935c ◽

1987 ◽

Vol 245 (3) ◽

pp. 935-935

Keyword(s):

Pore Size Distribution ◽

Pore Size ◽

Size Distribution ◽

Gel Chromatography ◽

Calibration Curves ◽

Molecular Masses

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Porosity and pore size distribution of shales: a case study of the Carynginia Formation, Perth Basin, Western Australia

The APPEA Journal ◽

10.1071/aj16182 ◽

2017 ◽

Vol 57 (2) ◽

pp. 660

Author(s):

M. Nadia Testamanti ◽

Reza Rezaee ◽

Jie Zou

Keyword(s):

Pore Size Distribution ◽

Pore Size ◽

Size Distribution ◽

Gas Adsorption ◽

Pore Network ◽

Pore Sizes ◽

Wide Range ◽

Pore Characterisation ◽

Shale Reservoirs ◽

Mercury Injection Capillary Pressure

The evaluation of the gas storage potential of shale reservoirs requires a good understanding of their pore network. Each of the laboratory techniques used for pore characterisation can be applied to a specific range of pore sizes; but if the lithology of the rock is known, usually one suitable method can be selected to investigate its pore system. Shales do not fall under any particular lithological classification and can have a wide range of minerals present, so a combination of at least two methods is typically recommended for a better understanding of their pore network. In the laboratory, the Low-Pressure Nitrogen Gas Adsorption (LP-N2-GA) technique is typically used to examine micropores and mesopores, and Mercury Injection Capillary Pressure (MICP) tests can identify pore throats larger than 3 nm. In contrast, a wider range of pore sizes in rock can be screened with Nuclear Magnetic Resonance (NMR), either in laboratory measurements made on cores or through well logging, provided that the pores are saturated with a fluid. The pore network of a set of shale core samples from the Carynginia Formation was investigated using a combination of laboratory methods. The cores were studied using the NMR, LP-N2-GA and MICP techniques, and the experimental porosity and pore size distribution results are presented. When NMR results were calibrated with MICP or LP-N2-GA measurements, then the pore size distribution of the shale samples studied could be estimated.

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Improved design and protocol for evapoporometry determination of the pore-size distribution

Journal of Membrane Science ◽

10.1016/j.memsci.2015.09.013 ◽

2015 ◽

Vol 496 ◽

pp. 334-343 ◽

Cited By ~ 13

Author(s):

Ebrahim Akhondi ◽

Farhad Zamani ◽

Jia Wei Chew ◽

William B. Krantz ◽

Anthony G. Fane

Keyword(s):

Pore Size Distribution ◽

Pore Size ◽

Size Distribution ◽

Improved Design

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Determination of pore size distribution by SETARAM DSC 101 (thermoporometry)

Thermochimica Acta ◽

10.1016/0040-6031(81)85142-8 ◽

1981 ◽

Vol 49 (1) ◽

pp. 49-52 ◽

Cited By ~ 10

Author(s):

M. Brun ◽

J.F. Quinson ◽

L. Benoist

Keyword(s):

Pore Size Distribution ◽

Pore Size ◽

Size Distribution

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Determination of T2 cut-off for shale reservoirs: a case study from the Carynginia formation, Perth Basin, Western Australia

The APPEA Journal ◽

10.1071/aj16184 ◽

2017 ◽

Vol 57 (2) ◽

pp. 664 ◽

Cited By ~ 1

Author(s):

M. Nadia Testamanti ◽

Reza Rezaee ◽

Yujie Yuan ◽

Dawei Pan

Keyword(s):

Pore Size Distribution ◽

Pore Size ◽

Size Distribution ◽

Petroleum Industry ◽

Bound Water ◽

Invasive Technique ◽

Sources Of Information ◽

Vacuum Oven ◽

Low Field ◽

Wide Range

Over recent decades, the low-field Nuclear Magnetic Resonance (NMR) method has been consistently used in the petroleum industry for the petrophysical characterisation of conventional reservoirs. Through this non-invasive technique, the porosity, pore size distribution and fluid properties can be determined from the signal emitted by fluids present in the porous media. Transverse relaxation (T2) data, in particular, are one of the most valuable sources of information in an NMR measurement, as the resulting signal decay can be inverted to obtain the T2 distribution of the rock, which can in turn be correlated with porosity and pore size distribution. The complex pore network of shales, which can have a large portion of pore sizes in the nanopore and mesopore range, restricts the techniques that can be used to investigate their pore structure and porosity. The ability of the NMR technique to detect signals from a wide range of pores has therefore prompted the quest for more standardised interpretation methods suitable for shales. Using low-field NMR, T2 experiments were performed on shale samples from the Carynginia formation, Perth Basin, at different saturation levels. The shale samples were initially saturated with brine and the T2 spectrum for each sample was obtained. Then, they were placed in a vacuum oven and their weight monitored until a constant value was reached. T2 curves were subsequently obtained for each of the oven-dried samples and a cut-off value for clay-bound water was calculated.

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