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Agilent - HPLC Columns - Zorbax

The Agilent ZORBAX column family is one of the most popular HPLC column families for reversed-phase HPLC. ZORBAX columns are based on traditional fully porous particles and offer the highest loading capacity and resolution. From ZORBAX Eclipse Plus C18 to sub-2 micron UHPLC columms, a wide selection of stationary phases and particle sizes allows you to fine-tune your selectivity to match your application.

Key features

  • Traditional, fully porous particles available in 1.8, 3.5, and 5 µm sizes. With selected products also available in 7 µm particles for preparative HPLC (see Prep LC columns section)
  • ZORBAX Eclipse Plus columns are the recommended starting point for method development and benefit from the ultimate performance from fully porous silica-based columns
  • ZORBAX StableBond columns offer the highest stability for low pH applications down to pH 1 while ZORBAX SB-Aq deliver robust, reproducible separations with highly aqueous mobile phases, including 100% water
  • ZORBAX Extend-C18 columns offer high efficiency for high pH applications up to pH 11.5
  • ZORBAX Bonus RP columns offer unique selectivity due to an embedded amide linkage in the C14-alkyl chain making them ideal for 100% aqueous mobile phases and for compounds that are not retained on standard reverse phase columns
  • ZORBAX Rx columns are made from highly pure (> 99.995 %) porous silica with a higher carbon load (12%)
  • ZORBAX Eclipse PAH columns deliver high resolution separation of the 16 PAHs in EPA 610 and have been specifically tested with PAHs for maximum reproducibility

ZORBAX Eclipse Plus

ZORBAX Eclipse Plus columns are the recommended starting point for method development and benefit from the ultimate performance from fully porous silica-based columns.

  • The ideal column for method development – excellent results for a wide range of compounds
  • High level of performance – peak shape, efficiency, resolution, and lifetime – with all sample types: acids, bases and neutrals
  • Superior reproducibility with more rigorous QA/QC testing
  • Improved, patented silica manufacturing with start-to-finish product control
  • Available in 1.8, 3.5, and 5 μm particle sizes for all analytical, high resolution, and fast LC analyses

Agilent ZORBAX Eclipse Plus columns provide the ultimate in performance for silica-based columns.

Peak shape is excellent for the most challenging basic compounds, improving efficiency and resolution with these sample types. These results are achieved by improvements in the silica manufacturing and bonding technology, which is completely controlled by Agilent.

Because of their high level of performance, Eclipse Plus columns are the ideal first choice for method development of all samples. If you need to achieve fast method development and superior productivity, then choose a column with high-resolution 1.8 μm particles. For standard methods, conventional 5 μm and Rapid Resolution 3.5 μm columns are your best choice. With all particle sizes, easy method transfer is possible. With more rigorous QA and QC testing, column lot-to-lot reproducibility is also improved, resulting in long-term reliable results for all analyses.


High resolution separation of 16 PAHs in EPA Method 610

  • Extensive range of particle sizes (1.8, 3.5 and 5 μm) and sizes for fast and high resolution separations
  • Each batch of material is specifically tested with PAHs for maximum reproducibility under expected operating conditions
  • Excellent performance using the high quality, improved silica of Eclipse Plus columns
  • Good for applications requiring "shape selectivity" or the separation of geometric isomers

Agilent ZORBAX Eclipse PAH columns are recommended for the separation of polycyclic aromatic

hydrocarbons. PAHs are considered priority pollutants and the analysis of these potentially carcinogenic

compounds in water, soil and food is of major importance. Eclipse PAH columns separate all 16 PAHS in

EPA method 610 quickly and with high resolution.


Four selectivity choices for method development optimization

• Good peak shape for basic, acidic and neutral compounds

• High performance over a wide pH range – pH 2-9

• Particle sizes from 1.8 to 7 μm

• Long lifetime with eXtra Dense Bonding and double endcapping

Agilent ZORBAX Eclipse XDB columns – C18, C8, Phenyl and CN – provide four bonded phase choices for method development optimization. These columns provide good peak shape over a wide pH range (2-9) for additional method development flexibility with one family of columns. Eclipse XDB columns can be used for method development at low pH (2-3) and the same column can be used for method development in the mid pH (6-8) region. In the mid pH region residual silanols are more active and tailing interactions are more likely. To overcome these interactions, Eclipse XDB columns are eXtra Densely Bonded and double endcapped through a proprietary process to cover as many active silanols as possible. The result is superior peak shape of basic compounds from pH 2-9. Eclipse XDB columns are available in 1.8, 3.5, 5 and 7 μm particle sizes for high speed, high resolution, analytical and prep scale separations.

ZORBAX 80Å StableBond

  • Longest column lifetime and best reproducibility for low pH separations – down to pH 1
  • Patented stable column chemistry allows use at high temperature and low pH without degradation
  • Six different bonded phases provide broad selectivity – SB-C18, SB-C8, SB-CN, SB-Phenyl, SB-C3, and SB-Aq
  • High purity (Type B) silica for good peak shape

Agilent ZORBAX StableBond columns use patented, unique, nonfunctional silanes with bulky diisobutyl (SB-C18) or diisopropyl (SB-C8, SB-C3, SB-Phenyl, SB-CN, and SB-Aq) side chain groups that sterically protect the key siloxane bond to the silica surface from hydrolytic attack at low pH. StableBond packing materials are not endcapped in order to provide exceptional stability and to maximize lifetime and reproducibility under acidic mobile phase conditions. The high purity, low acidity silica provides excellent peak shape with acidic, basic and neutral compounds making StableBond columns an excellent choice for low pH method development. ZORBAX StableBond columns are compatible with all common mobile phases, including very high aqueous mobile phases.


  • Recommended for alternate selectivity at low pH relative to Eclipse Plus C18, Eclipse XDB-C18 and
  • StableBond SB-C18; for higher temperature applications, StableBond is recommended
  • Higher carbon load than SB-C18 columns (12% vs. 10%)
  • High stability and good peak shape for low pH applications (up to pH 8)
  • Manufactured using dimethyloctadecylsilane and non-endcapped
  • ZORBAX Rx-C8 is the same product as SB-C8

ZORBAX 80Å Extend-C18

  • High efficiency and long life at high pH – up to pH 11.5
  • Unique bidentate bonding and double endcapping provides high pH stability
  • More efficiency and better peak shape than polymer-based columns
  • Improve retention, resolution and peak shape of basic compounds
  • High sensitivity for LC/MS separations of peptides

The Agilent ZORBAX Extend-C18 column uses a novel bidentate C18-C18 bonding technology to make it possible to develop high-resolution separations at high pH with a silica-based column. At high pH, non-charged basic compounds will not interact with the underlying silica. The result is high efficiency separations with superior peak shape and improved resolution. High pH separations are also the best choice for compounds that are more stable or more soluble in high pH solutions.

Some of the mobile phase buffer options for high pH include triethylamine, pyrrolidine, glycine, borate and ammonium hydroxide. Ammonium hydroxide at pH 10.5 is an excellent mobile phase modifier for the LC/MS of peptides and small molecules with improved sensitivity compared with TFA containing mobile phase at low pH. The Extend-C18 column is stable from pH 2-11.5 with good peak shape for all types of compounds. Extend-C18 columns also provide an additional selectivity choice at low pH.


  • Excellent peak shape for challenging basic compounds at low and mid pH
  • Unique reversed-phase selectivity
  • Novel bonding technology with embedded polar group and steric protection
  • Usable in 100% aqueous mobile phases

The Agilent ZORBAX Bonus-RP column has a polar amide group embedded in a long alkyl chain. This novel bonding reduces interactions between basic compounds and the silica support, improving peak shape for the most difficult basic compounds. Peak shape and column lifetime are further improved by triple endcapping. In addition, diisopropyl side groups provide steric protection against acid hydrolysis for good lifetime at low pH. The Bonus-RP column provides an alternate selectivity to C18 and C8 alkyl bonded phases.

ZORBAX Original Reversed-Phase Columns

Agilent Original ZORBAX columns are made with Type A silica and are useful for many applications of acidic or neutral compounds. These columns have a higher activity level and are therefore useful for separating isomers (e.g. cis-trans, geometric) or other compounds where silanol activity enhances selectivity. These columns are used in many established methods.

Zorbax Eclipse Plus performance

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