Polar peptides are quite amenable to HILIC separations; however, our experience with larger peptides has been only minimally successful - mainly due to solubility issues. Proteins are even more difficult due to the same issue. An additional problem with proteins is that they are often multiply charged. When IEX is performed on multiply charged analytes, you often get what is referred to as a rolling effect where the analyte interacts with ionic sites on the surface in many different ways as it 'rolls' down the column; this produces broad and misshapen peaks.
50264-U
Ascentis® Express 90 Å HILIC (5 μm) HPLC Columns
L × I.D. 3 cm × 3 mm, HPLC Column
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About This Item
Code UNSPSC :
41115700
Nomenclature NACRES :
SB.52
Le tarif et la disponibilité ne sont pas disponibles actuellement.
Produits recommandés
Nom du produit
Ascentis® Express HILIC, 5 μm HPLC Column, 5 μm particle size, L × I.D. 3 cm × 3 mm
Matériaux
stainless steel column
Niveau de qualité
Agence
suitable for USP L3
Gamme de produits
Ascentis®
Caractéristiques
endcapped: no
Fabricant/nom de marque
Ascentis®
Conditionnement
1 ea of
Paramètres
60 °C temp. range
600 bar max. pressure (9000 psi)
Technique(s)
HPLC: suitable
LC/MS: suitable
L × D.I.
3 cm × 3 mm
Superficie
90 m2/g
Impuretés
<5 ppm metals
Matrice
Fused-Core particle platform
superficially porous particle
Groupe de la matrice active
silica phase
Taille des particules
5 μm
Dimension de pores
90 Å pore size
pH de fonctionnement
1-8
Application(s)
food and beverages
Technique de séparation
hydrophilic interaction (HILIC)
normal phase
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Catégories apparentées
Description générale
Ascentis Express 5 μm HILIC is a high-speed, high-performance liquid chromatography column based on a 5-micron Fused-Core® particle design. The Fused-Core particle provides a thin porous shell of high-purity silica surrounding a solid silica core. This particle design exhibits very high column efficiency due to the shorter diffusion paths in the 0.6-micron thick porous shell around and an overall particle size of ~5-microns. The bare silica stationary phase of Ascentis Express 5 μm HILIC provides a column that can be used for traditional normal phase separations using non-polar, totally organic mobile phases or for aqueous normal phase chromatography with the typical reversed-phase mobile phases for hydrophilic interactive liquid chromatography (HILIC) of basic, acidic, or neutral compounds.
Column Characteristics
The Fused-Core particle has a surface area of ~ 100 m2/g and an average pore size of 90Å. The Fused-Core particles are 30% to 50% heavier than commercially available totally porous particles due to the density of the solid cores. Therefore, the effective surface area per column is similar to columns packed with totally porous particles having surface areas in the 160-200 m2/g range.
Column Characteristics
The Fused-Core particle has a surface area of ~ 100 m2/g and an average pore size of 90Å. The Fused-Core particles are 30% to 50% heavier than commercially available totally porous particles due to the density of the solid cores. Therefore, the effective surface area per column is similar to columns packed with totally porous particles having surface areas in the 160-200 m2/g range.
Informations légales
Ascentis is a registered trademark of Merck KGaA, Darmstadt, Germany
Fused-Core is a registered trademark of Advanced Materials Technology, Inc.
Code de la classe de stockage
11 - Combustible Solids
Classe de danger pour l'eau (WGK)
WGK 3
Point d'éclair (°F)
Not applicable
Point d'éclair (°C)
Not applicable
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Retrouvez la documentation relative aux produits que vous avez récemment achetés dans la Bibliothèque de documents.
Paweł Kubica et al.
Journal of pharmaceutical and biomedical analysis, 127, 184-192 (2016-01-20)
Hydrophilic interaction liquid chromatography (HILIC) coupled with tandem mass spectrometry (MS/MS) was used to separate artificial and natural sweeteners approved for use in European Union (EU). Among three tested HILIC columns (BlueOrchid PAL-HILIC, Ascentis Express Si and Acclaim™ Trinity™ P2)
Imran Ali et al.
Biomedical chromatography : BMC, 26(8), 1001-1008 (2012-01-13)
Superficially porous silica particles columns (SPSPCs) are manufactured by different companies. The most common have the brand names Halo, Ascentis Express and Kinetex. These columns provide super fast, sharp peaks and moderate sample loading and back pressure. These are available
Tiziana Bertolini et al.
Journal of chromatography. A, 1365, 131-139 (2014-09-23)
A simple, sensitive and fast hydrophilic interaction liquid chromatography (HILIC) method using ultraviolet diode-array detector (UV-DAD)/electrospray ionization tandem mass spectrometry was developed for the automated high performance liquid chromatography (HPLC) determination of sodium risedronate (SR) and its degradation products in
Jan Soukup et al.
Journal of chromatography. A, 1374, 102-111 (2014-12-30)
Excess adsorption of water from aqueous acetonitrile mobile phases was investigated on 16 stationary phases using the frontal analysis method and coulometric Karl-Fischer titration. The stationary phases include silica gel and silica-bonded phases with different polarities, octadecyl and cholesterol, phenyl
Alexandre Grand-Guillaume Perrenoud et al.
Journal of chromatography. A, 1360, 275-287 (2014-08-19)
Superficially porous particles (SPP), or core shell particles, which consist of a non-porous silica core surrounded by a thin shell of porous silica, have gained popularity as a solid support for chromatography over the last decade. In the present study
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Can peptide or protein samples be analyzed using HILIC columns?
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How should I store the Ascentis Express HILIC column?
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Long-term storage of silica-based columns is best in 100% acetonitrile. Columns may be safely stored for short periods (up to 3 or 4 days) in most common mobile phases. However, when using buffers, it is best to remove the salts to protect both the column and the HPLC equipment by first flushing the column with the same mobile phase without the buffer (e.g., when using 90/10 ACN/buffer, flush the column with 90/10 ACN/H2O) to eliminate any concern about salt precipitation or corrosion from the salts then flush the column with 100% acetonitrile for storage.Before storing the column, the end-fittings should be tightly sealed with the endplugs that came with the column to prevent the packing from drying.
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Would you advise addition of a buffer when using diol or amide stationary phase?
1 answer-
Yes. if possible you should always have at least a small amount of buffer in a HILIC system to help mediate/control IEX and other polar interactions that are bound to be present (even if at a low level). It is not so much the "buffering capacity" that is important, but the presence of the competing ions. We have found that their presence helps with day to day and column to column reproducibility. There are times when you need to eliminate the buffer, but aside from special circumstances, our recommendation is to include them.
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How does the flow rate influence the water layer on the column?
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We are not aware of any systematic studies with respect to the impact of flow rate on HILIC separations. Our concern would be that as you move to higher flow rates, you might observe peak shape issues due to the slow kinetics of IEX and adsorption mechanisms. If the retention mechanisms for a given system are partition dominated, this should be of less concern. It will be a case by case cause and effect.
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What is the Department of Transportation shipping information for this product?
1 answer-
Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product.
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When referring to the pH of the mobile phase (pH 3, pH 4, etc.), does that refer to the aqueous part of the mobile phase?
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Typically when we refer to pH in HILIC, we use the effective pH or the pH as measured after the addition of organic. The point is that we should always define what pH we are stating. The common way to distinguish is using notation of w/w pH or s/w pH (usually superscript/subscript). The notations mean superscript = solvent the pH is measured in (s would indicate some mixture of aqueous:organic) and the subscript = the solvent the pH meter is calibrated in (typically water (or w) as we readily have calibration standards).
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Why is it recommended to run isocratically for HILIC methods?
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When running in HILIC mode, both isocratic and gradient practices result in instability. If you keep the re-equilibration times constant, gradient should not be a problem, but changing this parameter can have a significant impact. It is not so much that it is bad as it is different than we are used to in reversed phase. Usually, we assume that once equilibrated (5, 10, 15 min, etc.), we can leave the system for any time period and come back to the same results. This does not appear to be the case in our studies of HILIC. Knowing that the re-equilibration time has an impact, you should get in the habit of making several injections with known re-equilibration times prior to making any development decisions. To get around this, isocratic runs are recommended. Attached are two posters; the first was presented at HPLC 2013 (Amsterdam) and the second was presented at Balaton Symposium on High Performance Separation Methods 2013 (Hungary). Both show 'reproducibility' at any set re-equilibration time is good but both show that if you change the re-equilibration time; then retention, peak shape and selectivity can change especially where ionic interactions are prevalent.
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In HILIC separations, what happens if the sample is an aqueous matrix? Does it always have a negative effect?
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Yes, it would be highly preferential (especially in this case where you want partitioning to dominate) to inject in high organic. That said, you can 'get away' with it if the injection volume can be kept small - much like we can inject low volumes of stronger solvents in RP mode, if needed. What you will want to do to minimize impact is to get as much retention on the analytes of interest as you can, this helps give the sample solvent some time to dissipate and negate the effects.
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When you recommend only changing one parameter at a time, does this also refer to the total ionic strength?
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If you change organic, try to keep the overall buffer concentration (and all other parameters, for that matter) constant. There are times when you will want to change both and perhaps pH/temp/etc. simultaneously, but that drastically complicates the system and thus should be avoided, if possible.
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What steps should be taken to maximize column life?
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To maximize column life, ensure that samples and mobile phases are particle-free. The use of guard columns or an in-line filter with 0.5 μm porosity between the sample injector and the column is highly recommended. The 2 μm porosity frits on Ascentis Express 5 μm HILIC columns are less subject to pluggage than are the 0.5 μm frits typically used with other small-particle columns. Should the operating pressure of the column suddenly increase beyond normal levels, reversing the flow direction of the column may be attempted to remove debris on the inlet frit.
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