If the acids are hydrophilic or you can adjust the pH to make them hydrophilic enough, any of the phases that exhibit HILIC partitioning are possible (bare silica, OH5, diol, Zwitterionic, amide). We typically go with the OH5 first to try and avoid any negative impacts on the like charge.
53934-U
Ascentis® Express 90 Å HILIC (2.7 μm) HPLC Columns
L × I.D. 5 cm × 2.1 mm, HPLC Column
Sinônimo(s):
Core-shell (SPP) Fused Core Si HPLC column
About This Item
Produtos recomendados
Nome do produto
Ascentis® Express HILIC, 2.7 μm HPLC Column, 2.7 μm particle size, L × I.D. 5 cm × 2.1 mm
Materiais
stainless steel column
Agency
suitable for USP L3
linha de produto
Ascentis®
Características
endcapped: no
fabricante/nome comercial
Ascentis®
embalagem
1 ea of
Parâmetros
≤100 °C temp. range
600 bar max. pressure (9000 psi)
técnica(s)
HPLC: suitable
LC/MS: suitable
UHPLC-MS: suitable
UHPLC: suitable
C × D.I.
5 cm × 2.1 mm
área da superfície
135 m2/g
Impurezas
<5 ppm metals
Matriz
Fused-Core particle platform
superficially porous particle
Grupo ativo da matriz
silica phase
tamanho de partícula
2.7 μm
tamanho de poro
90 Å
pH operacional
1-8
aplicação(ões)
food and beverages
técnica de separação
hydrophilic interaction (HILIC)
normal phase
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Categorias relacionadas
Descrição geral
Visit the Ascentis Express home page for more information on this new column technology.
Informações legais
Aplicação
necessário, mas não fornecido
produto relacionado
pré-cartucho
Código de classe de armazenamento
11 - Combustible Solids
Classe de risco de água (WGK)
WGK 3
Ponto de fulgor (°F)
Not applicable
Ponto de fulgor (°C)
Not applicable
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Artigos
For separation of polar compounds including polar neutrals, polar acids, and polar and non-polar basic amines use our Ascentis® Express HILIC column.
Protocolos
We offer the tools for the analysis of the metabolites; including certified reference standards, enzymes, substrates, and chromatographic products.
We offer the tools for the analysis of the metabolites; including certified reference standards, enzymes, substrates, and chromatographic products.
Chromatograms
application for HPLCapplication for HPLCapplication for HPLCapplication for HPLCMostrar mais-
What column do you recommend for an anionic compound?
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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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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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What flow rate should I use with Ascentis® Express HPLC Columns?
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Based on the minimum in the van Deemter curves, higher flows than 5um particle columns are required in order to maximize Ascentis Express column efficiency. The suggested starting point for flow rate for Ascentis Express columns: 1.6 mL/min for 4.6 mm ID; 0.8 mL/min for 3.0 mm ID; and 0.4mL/min for 2.1 mm ID.
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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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Can I use Ascentis Express on a UHPLC system?
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Yes. Ascentis Express columns are packed in a way making them suitable for these ultra high pressure instruments. In fact, Ascentis Express outperforms sub-2 μm micron columns on many applications since Ascentis Express provides the benefits of sub-2 μm particles but at much lower back pressure. These benefits include the capability of providing fast HPLC and higher resolution chromatography. The Fused-Core particle consists of a 1.7 μm solid core and a 0.5 μm porous shell. A major benefit of the Fused-Core particle is the small diffusion path (0.5 μm) compared to conventional fully porous particles. The shorter diffusion path reduces axial dispersion of solutes and minimizes peak broadening.
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Can peptide or protein samples be analyzed using HILIC columns?
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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.
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Can I use Ascentis Express on any type of HPLC system?
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Ascentis Express HPLC columns are capable of use on standard HPLC systems as well as UHPLC systems. Columns are packed in high pressure hardware capable of withstanding the pressures used in UHPLC systems.
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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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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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