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.
推薦產品
產品名稱
Ascentis® Express HILIC, 2.7 μm HPLC色谱柱, 2.7 μm particle size, L × I.D. 15 cm × 2.1 mm
材料
stainless steel column
品質等級
agency
suitable for USP L3
產品線
Ascentis®
特點
endcapped: no
製造商／商標名
Ascentis®
包裝
1 ea of
參數
≤100 °C temp. range
600 bar max. pressure (9000 psi)
技術
HPLC: suitable
LC/MS: suitable
UHPLC-MS: suitable
UHPLC: suitable
長度 × 內徑
15 cm × 2.1 mm
表面積
135 m2/g
雜質
<5 ppm metals
基質
Fused-Core particle platform
superficially porous particle
基質活性組
silica phase
粒徑
2.7 μm
孔徑
90 Å
工作pH值
1-8
應用
food and beverages
分離技術
hydrophilic interaction (HILIC)
normal phase
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一般說明
通过使用Fused-Core® 粒子技术，Ascentis Express HPLC色谱柱在保持较低的反压力的同时，可以为您提供2μm以下颗粒的高速和高效率。高效和低背压的结合能使UPLC®（或其他超高压系统）用户以及常规HPLC用户受益。
查看Ascentis Express主页获取关于该全新色谱柱技术的更多信息。
查看Ascentis Express主页获取关于该全新色谱柱技术的更多信息。
法律資訊
Ascentis is a registered trademark of Merck KGaA, Darmstadt, Germany
Fused-Core is a registered trademark of Advanced Materials Technology, Inc.
UPLC is a registered trademark of Waters
相關產品
防護柱套
儲存類別代碼
11 - Combustible Solids
水污染物質分類（WGK）
WGK 3
閃點（°F）
Not applicable
閃點（°C）
Not applicable
從最近期的版本中選擇一個：
分析證明 (COA)
Lot/Batch Number
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
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
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
文章
For separation of polar compounds including polar neutrals, polar acids, and polar and non-polar basic amines use our Ascentis® Express HILIC column.
條款
We offer the tools for the analysis of the metabolites; including certified reference standards, enzymes, substrates, and chromatographic products.
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How does the flow rate influence the water layer on the column?
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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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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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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 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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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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How can I measure my instrument bandwidth (IBW) and determine what Ascentis® Express HPLC Columns can be used with minimal efficiency loss created by too much internal instrument volume?
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The Guide to Dispersion Measurement has simple instructions on how to measure IBW and can be found at sigma-aldrich.com/express.
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What column do you recommend for an anionic compound?
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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.
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Can Ascentis® Express HPLC Columns be used for LC-MS?
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Express Fused-Core™ particles were designed with LC-MS in mind. Even extremely short column lengths exhibit sufficient plate counts to show high resolving power. The flat van Deemter plots permit resolution to be maintained at very high flow rates to maximize sample throughput. All Ascentis stationary phases have been evaluated for MS compatibility during their development, and the Express phases are no exception. You can expect extremely low column bleed and background while maintaining longest possible column lifetime. A bonus of Ascentis Express columns for high throughput UHPLC and LC-MS is that they are extremely rugged and highly resistant to plugging, a very common failure mode for competitor columns.
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Is there anything special I need to do to my HPLC system to use Ascentis Express?
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Nothing special is required to use Ascentis Express HPLC columns. To obtain the full benefits of Ascentis Express, one should minimize dispersion or instrument bandwidth in the HPLC system (tubing, detector flow cell) as well as confirm the detector response system is set at a fast level. For more information, request Guidelines for Optimizing Systems for Ascentis Express Columns (T407102)
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