Στήλες HPLC & UHPLC

Ion Exchange Chromatography (IEC)

Ion Exchange Chromatography (IEC) is a technique based on the difference in the strength of the interaction between a sample ion and an oppositely charged functional group on the support. The sample ion competes for the functional group with a counter ion that has been added to the mobile phase as a salt. Elution is most often accomplished by increasing the salt concentration over time.

Ion exchange chromatography is the most common separation mode for protein purification schemes. Biomolecules generally have charged groups on their surfaces, which change with the pH of the solution.

Anion Exchange Chromatography is performed with either a strong anion exchange column, containing a quaternary ammonium ion, or with a weak anion exchanger, having either a tertiary or secondary amine functional group, such as DEAE (diethylaminoethyl). A counter ion, often Cl-, maintains electroneutrality.

Cation Exchange Chromatography is performed with either a strong cation exchanger, containing a bonded sulfonic acid group, such as sulfopropyl (SP), or with a weak cation exchanger, containing a weak acid such as carboxymethyl (CM). A counter ion, often Na+, maintains electroneutrality. The advantage of strong vs. weak ion exchangers is that the first are charged over a wider pH range. Weak ion exchangers often provide slightly different selectivity from strong exchangers.

In ion exchange chromatography, the pH of the mobile phase buffer must be between the pI or pKa of the charged molecule and the pKa of the charged groups on the solid support. For example, a molecule with a pI of 8.2 is run in a mobile phase buffer at pH 6.0 with the solid support pKa at 1.2 in cation exchange chromatography. In anion exchange chromatography a molecule with a pI of 6.8 is run in a mobile phase buffer at pH 8.0 with the solid support pKa at 10.3.

Size Exclusion Chromatography (SEC)

Size Exclusion Chromatography (SEC) separates molecules based on their size, or more precisely, their hydrodynamic volume. It is based on the discrimination of individual sample components by the pores of the packing material. Large sample molecules cannot or can only partially penetrate the pores and elute from the column first, whereas smaller molecules can access all or a larger number of pores and elute later. SEC is the only mode of chromatography that does not involve interaction with a stationary phase by means of adsorption or partitioning of the solutes.

The terms SEC, GFC (gel filtration chromatography) and GPC (gel permeation chromatography) all refer to the same chromatographic technique. In GFC an aqueous mobile phase is used, while an organic mobile phase is employed in GPC. The general term SEC covers both uses.

SEC is the dominant mode of separation for natural and synthetic polymers:
GFC is the term used for the size-based separation of water-soluble polymers, for example biopolymers or natural polymers.
GPC is the term used for the size-based separation of polymers soluble in organic solvents.

Size exclusion chromatography columns are traditionally packed with porous polystyrene divinylbenzene (PS-DVB) or silica particles. PS-DVB columns are commonly used for the analysis of synthetic polymers in organic solvents, while silica-based columns are used for the separation of biopolymers.

Avantor® Hichrom other columns

Eprogen, Exsil, Avantor^® Hichrom C8, C18 and RPB, Avantor^® Hichrom PAH2, Avantor^® Hichrom Chiral, Inertsil, LiChrosorb, LiChrospher, NUCLEOSIL, Avantor^® Ultrasphere, ZORBAX

HPLC columns, Avantor® Partisil® & Partisphere®

Commercially available spherical silicas and it continues to provide and reproducible, high efficiency separations, Avantor^® Partisphere^® columns are available in a wide range of surface chemistries including two application specific phases.

Reprospher

Your workhorse
Reprospher media are based on a 100 A ultrapure silica and are fully scalable from UPLC (1.9 µm particles) to preparative and process scale applications.
Among the offered phases there are some unique selectivities such as a wide range of aromatic specialty phases, phases with polar selectivities and unique phases for achiral SFC.

ReproSil XR

Premium performance at exceptional value
An allround and fully scalable spherical Silica from 1.5 to 15 µm with an extra high purity.
The metal content is less than 100 ppb.
The silica impresses with its very narrow pore size distribution this make 99 % of the surface accessible for the separation.
The uniform bonded phase coverage translates to symmetrical peaks for acids/bases, and predictable reversed phase selectivity.
Because of its very low metal content it also impressed with a high pH stability.

ReproSil Saphir

Alternative to Luna C18
A low metal content spherical silica media scalable from sub-2-micron to 10 µm particles with high carbon load for small molecules and peptides and wide pore ion exchange media for protein and enzyme analysis and purification.

ReproSil-Pur

Specifically designed for pharmaceutical and biotechnical separations.
A robust modern and all-purpose ultra-high purity spherical silica media scalable from UPLC to prep.
Various pore sizes are available to cover applications for small molecules up to biomolecules.
State-of-the-art surface modification technologies are employed for normal and reversed phase media including shape selective, high carbon load as well as water wettable alkyl phases.

Micro/NanoLC Columns

Miniaturisation of liquid chromatography in combination with mass spectrometry has several advantages including improvements in sensitivity, especially at low concentration levels and dramatically reduced solvent consumption, compared to conventional HPLC or UHPLC. With further method optimisation, run times can also be reduced giving further savings in solvent use or time. To meet the requirements of MicroLC/CapillaryLC/NanoLC YMC offers capillary columns specifically designed to use with the corresponding chromatography systems.

Normal Phase (NP) Columns

Whilst historically it was the earliest form of HPLC, normal phase separations have recently received less attention due to the belief that it is complicated and unpredictable. However, normal phase chromatography is a powerful tool for the separation of positional isomers that are difficult to separate in reversed phase mode. Due to a rigid surface, compared to the more flexible carbon chains of reversed phases, the analytes are influenced by well-defined steric interaction with polar groups. YMC offers columns packed with non-bonded silica or with silica gel modified with polar groups

HILIC Columns

HILIC HPLC/UHPLC columns from YMC are rugged stationary phases which provide improved LC/ESI-MS response, direct SPE solvent compatibility and complementary selectivity to reversed phases. This is important to R&D and drug metabolism scientists since the impurity or metabolite is frequently more polar and present at much lower concentrations than the parent compound. With YMC HILIC columns, these very polar compounds elute later than the higher hydrophobic parent compound, thereby minimizing the MS ion suppression that can occur at the beginning of the chromatogram.

Chiral Columns

YMC offers several solutions for separating chiral compounds with different chiral selectors and different chiral separation mechanisms. The selectors are either coated/immobilised or bonded to the support material which has different pore sizes dependent on the selector. According to the selector chiral chromatography can be performed in NP, RP and/or SFC mode.

Biochromatography Columns

RP Bioseparation,
Ion Exchange (IEX),
Size Exclusion (SEC),
Hydrophobic Interaction (HIC)

Reversed Phase (RP) Columns

YMC’s selection of reversed phase (RP) UHPLC/HPLC columns
YMC-Triart,
YMC-Pack ProFamily,
YMC RP Classics,
Meteoric Core

Application Specific HPLC Columns

Designed for key pharmaceutical and environmental applications, these columns utilize novel and unique chemistries to provide superior resolution with ease of use.

Size Exclusion HPLC Columns

Want high resolution separation of water-soluble polymers? Our size exclusion columns (SEC) are available in tailored pore sizes to cover a broad range of molecular weight.