How do I know what size pore for HPLC?
As a general rule, a pore diameter of 10 nm or less should be used for analytes below 3,000 Da. A pore diameter of 10 – 13 Da is recommended for samples in the range of 3,000 – 10,000 Da. For samples above 10,000 Da, including peptides and proteins, a 30 nm material provides the best efficiency and peak shape.
What is the diameter of HPLC column?
HPLC Instrument Considerations Standard columns for reversed phase, normal phase, and ion exchange chromatography typically range from 3.9 to 4.6 mm internal diameter and 15, 25, and 30 cm in length. Standard columns for gel permeation chromatography (GPC) are 7.8 mm by 30 cm. Flow rates are typically 1 to 2 mL/min.
What effect does column particle size have on HPLC?
Particle size (dp), or the mean diameter of the spherical supports used to pack a column, is a physical dimension that has a significant impact on the performance of an HPLC column. Smaller particle sizes have been shown to offer higher peak efficiencies.
What is the correct range of particle size of stationary phase in HPLC?
The standard particle size used in HPLC today is ~ 3.5 to 5.0 microns. Other common sizes include 2.9 microns as well. Far less common are the particles <= 2.5. For preparative purifications, we typically use much larger particles (~ 10 to 25 microns).
What is column pore size?
Pore size is the average size of a pore in a porous packing. Its value is typically expressed in angstroms. Therefore, the pore size of the packing material in your HPLC column is important, since the molecules must ‘fit’ into the porous structure in order to interact with the stationary phase.
What is pore radius?
Here we determined the critical pore radius, which is the radius of the largest sphere that can freely pass through a porous medium, using the water expulsion method, an experimental technique measuring the pressure at which gas passes through a water-saturated porous medium.
What is pore size in HPLC column?
Pore size is the average size of a pore in a porous packing. Its value is typically expressed in angstroms. The pore size determines whether a molecule can diffuse into and out of the packing.
What is the internal diameter of my LC tubing?
Yellow = 0.007” ID. Blue/Tan = 0.010” ID. Orange = 0.020” ID.
Why are smaller particles better for HPLC?
Column length and particle size of stationary phase play a crucial role in separation efficiency and the column back pressure of HPLC columns. Particle size refers to the average diameter of the stationary phase particles. Smaller particles improve separation efficiencies.
What size is a particle?
Particle sizes are measured in microns (μ). A micron is 1/1000 mm. or 1/25,400 in. A millimicron (mμ) is 1/1000 of a micron, or 1/1,000,000 mm. Usually particle size is designated as the average diameter in microns, although some literature reports particle radius.
What is the normal pore size?
Through computer simulation an optimum value is found to be within the range of 30–60 μm [17]. Membrane tortuosity is defined as the ratio of pore length to membrane thickness.
How big is a pore?
Facial pores are typically visible to the naked eye and can range from approximately 250 to 500 micrometers in size. The usual size range varies depending on factors such as skin tone and age. There is no consensus on how to determine whether a pore is considered large.
What is the size of pore in HPLC?
The pore size of HPLC particles can vary widely from product to product, but should be consistent within a particular product line of columns. There are two general categories of pore sizes. Small-pore particles have pores ranging from about 6-15 nm (60-150 Å), with the majority in the 8-12-nm range.
What is the surface area of a pore column?
The surface area of a particle is inversely proportional to the pore diameter, so a 5-μm particle size, 10-nm pore column will have approximately three times the surface area as a 5-μm, 30-nm pore column. Because retention is directly related to surface area, use of large-pore columns usually is not desirable when small-pore columns can be used.
Why is pore size important in column chromatography?
In summary, the pore size of a column is selected so that the sample molecules have easy access to the pores. Smaller-pore columns are desired because of their higher surface area, as long as the analytes are sufficiently small to easily enter the pores.
What is the particle size of an LC column?
The 3.5 µm particle size operates at a routine operating pressure and may be used on all LCs, including those with a 400-bar operating limit. Short (50 mm and shorter) 1.8 µm columns may be employed on optimized standard LCs, while longer columns may require a higher-pressure LC or UHPLC, operating at pressures from 600 to 1300 bar.