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Chromolith® HPLC & UHPLC columns

electron microscope image of monolithic silica structure

Electron-Microscope photo of monolithic silica structure.

Introduction

Chromolith® HPLC columns are designed using sophisticated monolithic silica technology. These columns are made from a continuous piece of ultra-pure, fully porous silica (Type B) using a sol-gel process, resulting in a well-defined bimodal pore structure with both macropores and mesopores in the micro- and nanometer range. The silica skeleton's high permeability and porosity results in significantly lower column back pressure, allowing for more variable flow rates and the use of mobile phases with higher viscosity than typical particle columns. This feature allows for high-throughput analysis while retaining separation efficiency and peak capacity.

Download & Read the Chromolith® Monolithic Silica HPLC Columns Brochure.

The revolutionary, bimodal pore structure of Chromolith® columns provides unique benefits:

  • Rapid separations at very low column back-pressure
  • Standard HPLC instruments are fully compatible with all Chromolith® columns and UHPLC instruments are fully compatible with Chromolith® 2 mm I.D. columns.
  • Matrix-rich samples (such as food, life science samples, or complex pharmaceutical formulations) can be analyzed without the need for sophisticated and time-consuming sample preparation. Guard column cartridges are also available to extend lifetime and applicability even further.
  • Cost-savings are achieved as the column lifetimes are much longer than for particulate HPLC columns, in particular when analyzing matrix-rich samples.
  • Complex multi-component samples can be separated either by using Chromolith® HighResolution (HR) columns or by using long very high-efficiency columns formed by connecting two or more Chromolith® columns together. The low-column backpressure makes this possible.
  • 2 mm I.D. Columns are best suitable for LC-MS methods and provide higher sensitivities
  • Easy transfer of methods from a particulate column to a Chromolith® column.
  • The very low column backpressure allows the use of sustainable/greener mobile phases such as bioethanol.
  • Chromolith® WP 300 columns have 300 A mesopores and therefore are an excellent solution for the separation of larger Biomolecules

Classic Particulate Columns Versus Chromolith® HPLC Columns

Using HPLC columns with silica particles often leads to excessive back pressure. This can harm both the column and the HPLC system, thus traditional HPLC columns have a limited length and potential plate count. Attempts have been made to raise the plate count by reducing particle size, however, this causes undesirable back pressure and restricts the number of separations that can be satisfactorily achieved.

Learn more about the UHPLC Analysis of Diclofenac in Gel using a Monolithic Silica ColumnAnalysis of Clobetasol propionate in whitening cream on Chromolith® HighResolution RP-18e 100 x 2 mm I.D. Column, and Cannabinoids Analysis in Cannabis Using a High Resolution Monolithic Silica HPLC Column.

Chromolith® HPLC columns are the best choice for further accelerating the process. Chromolith® columns, with their unique bimodal pore structure, deliver outstanding separations in a fraction of the time that a typical particulate column does. This allows for faster speeds and increased sample throughput while maintaining lower back pressure.

Chromolith® columns are available with several pore structures enabling the optimal performance for different demands and with multiple phase modifications:

 
 Macropore: 2 µm
Mesopore: 130 Å
Macropore: 1.15 µm
Mesopore: 150 Å 
Chromolith® HighResolution RP-18e 
Chromolith® HighResolution RP-8e 
Chromolith® RP-18e 
Chromolith® RP-8e 
Chromolith® CN 
Chromolith® Diol 
Chromolith® NH2 
Chromolith® Si 
Chromolith® 2 mm I.D.: 1.5 µm
Chromolith® Prep 25 mm I.D. 3 µm Macropores

Chromolith® RP-18 endcapped Monolithic Silica HPLC Columns

Chromolith® RP-18 endcapped columns are designed for fast, robust separation of hydrophobic to medium polar compounds at low back pressure. They are well-suited for matrix-rich samples and offer high throughput, lower matrix sensitivity, and extended column lifetime. Chemically modified with n-alkyl chains for high ligand density and fully endcapped to reduce silanol group activity, these columns are ideal for reversed-phase chromatography.

These columns are made from high-purity, metal-free silanes and undergo the same surface modification techniques as high-end particle-packed columns. As a result, their chromatographic selectivity is comparable to that of high-quality C18-encapped reversed-phase particle columns. This enables their easy incorporation into standard procedures for generating new protocols, as well as the conversion of existing particle column-based methods to these columns.

Chromolith® RP-18e columns are listed in the US Pharmacopoeia columns under the category L1.

Silica type

High-purity silica (Type B)

Particle size

Monolithic

Macropore size

2 μm

Mesopore size

13 nm (130 Å)

Pore volume

1.0 mL/g

Total porosity

> 80%

Surface area

300 m2/g

Surface modification

Octadecylsilane; C18 endcapped

USP classification

L1

Carbon content

18%

Chromolith® RP-18 endcapped columns are available in column inner dimensions of 4.6 mm, 3 mm and 2 mm for analytical applications as well as in 10 mm, and 25 mm i.D. for Semi-preparative use. In addition, capillary columns are available.

Chromolith® HighResolution RP-18 endcapped HPLC Columns

Chromolith® HighResolution RP-18 endcapped columns combine the advantages of high flow rates, low matrix sensitivity, low back pressure, and extended column lifetime with even higher efficiency. These columns are designed for quick, robust, and efficient separation of hydrophobic to medium polar chemicals. They are a perfect alternative to sub-3 µm particulate columns and give equivalent results to core-shell particle columns at a significantly lower back pressure. Furthermore, Chromolith® HighResolution columns last more than 30% longer than particle columns.

These columns are made from high-purity silica with a bimodal structure and have smaller macropores (1.15 μm) than conventional Chromolith® columns. This results in at least 50% higher efficiency and improved peak symmetry. While the back pressure is larger than in normal Chromolith® columns, it is still less than half that of particle columns of comparable size. Because the chemical basis of Chromolith® HighResolution RP-18e columns is the same as that of high-end particulate silica columns (such as Purospher® columns), they can be easily used in standard methods when developing new protocols, and method transfer from particulate columns to monolithic Chromolith® RP-18 columns.

Features & Benefits

  • High throughput at elevated flow rates
  • Lower matrix sensitivity
  • Comparable performance to sub-3 µm particle-packed columns
  • At least 50% higher efficiency than standard Chromolith® columns
  • Back pressure is less than half that of particulate columns
  • Over 30% longer column lifetime
  • Capability for flow gradients and column coupling
  • Simple method transfer from particulate to monolithic columns

Comparison of Chromolith® and Chromolith® HighResolution columns

A triangular radar chart that compares the performance characteristics of two HPLC columns: Chromolith® (depicted with green data points) and Chromolith® HighResolution (depicted with purple data points). The chart has three axes arranged in a triangular layout. At the top is the "Number of theoretical plates per meter" axis, ranging from 0 to 150,000 in increments of 50,000. Chromolith® HighResolution reaches the maximum of 150,000 plates, while Chromolith® is marked around 90,000. The left axis represents "Back pressure (bar) at 1 mL/min flow rate of Acetonitrile/Water (50/50, v/v)" and ranges from 0 to 30 bar in increments of 10. Chromolith® shows a lower back pressure of about 10 bar, whereas Chromolith® HighResolution has a higher back pressure close to 20 bar. The right axis indicates "Column lifetime compared to a particulate column," ranging from 0 to 2x in increments of 1x. Chromolith® has a longer column lifetime, indicated as 2x, compared to Chromolith® HighResolution, which has a lifetime of 1x. The chart illustrates the trade-offs between higher back pressure, increased number of theoretical plates, and column lifetime for these two types of HPLC columns, showing that Chromolith® HighResolution offers higher efficiency at the cost of increased back pressure and reduced column life compared to Chromolith®.

Chromolith® HR columns deliver similar results to 3 μm fully porous particles (FPP) or 2.7 μm superficially porous particles (SPP) columns, but at much lower back pressures.

A chromatogram graph that displays the separation of seven compounds using a silica monolith Chromolith® HighResolution RP-18e column at 46 bar, analyzed over a retention time period of 10 minutes. The x-axis is labeled "Retention Time (minutes)" and ranges from 0 to 10, with major tick marks every 2 minutes. The y-axis is labeled "Intensity (mAU)" and ranges from -50 to 300, with major tick marks every 50 mAU. The chromatogram shows seven distinct peaks numbered 1 through 7, with varying intensities. Peak 1 has a low intensity, appearing just after the 1-minute mark. Peak 2 is sharper and taller, occurring at approximately 2 minutes. Peak 3 is the highest, reaching close to 250 mAU, around 3 minutes. Peaks 4 and 5 are smaller, appearing at roughly 3.5 and 4 minutes, respectively. Peaks 6 and 7 are spaced farther apart, appearing around 5 and 6 minutes, with moderate intensities. The baseline remains stable and consistent before and after the peaks, indicating effective separation and detection of the compounds.

Silica monolith: Chromolith® HighResolution RP-18e
Pressure = 36 bar

A chromatogram graph depicting the separation of seven peaks, each representing a distinct compound using a fully porous silica particle (FPP) C18 column at 146 bar, measured over a retention time span of 10 minutes. The x-axis is labeled "Retention Time (minutes)" and ranges from 0 to 10, with major tick marks at 2-minute intervals. The y-axis is labeled "Intensity (mAU)" and extends from -50 to 300, with major tick marks every 50 mAU.The chromatogram illustrates seven numbered peaks (1 to 7), each differing in intensity and retention time. Peak 1 appears shortly after the 1-minute mark with a small intensity. Peak 2 is taller, occurring at approximately 2 minutes. Peak 3 is the highest and most prominent, reaching around 250 mAU at 3 minutes. Peaks 4 and 5 have moderate heights and are closely spaced, occurring around 4 and 5 minutes, respectively. Peaks 6 and 7 are spaced more widely, appearing at roughly 6 and 7 minutes, with moderate intensities. The baseline is stable before the first peak and after the last peak, suggesting good separation and clear detection of each compound.

Fully porous silica particle (FPP) C18, 3μm
Pressure= 146 bar

A chromatogram graph showing the separation of seven peaks, each corresponding to a different compound using a superficially porous silica particle C18 column (SPP) at 170 bar, analyzed over a retention time of 10 minutes. The x-axis is labeled "Retention Time (minutes)" and ranges from 0 to 10, with major tick marks at 2-minute intervals. The y-axis is labeled "Intensity (mAU)" and spans from -50 to 300, with major tick marks every 50 mAU. The chromatogram features seven numbered peaks (1 through 7), each with distinct intensities and retention times. Peak 1 is the smallest, appearing just after the 1-minute mark. Peak 2 is taller, occurring around 2 minutes. Peak 3 is the most prominent, reaching nearly 250 mAU at approximately 3 minutes. Peaks 4 and 5 are moderately high and appear close to each other around 4 and 5 minutes, respectively. Peaks 6 and 7 are less intense, with Peak 6 appearing near 6 minutes and Peak 7 around 7 minutes. The baseline is stable and flat before the first peak and after the last peak, indicating effective compound separation and consistent performance of the chromatographic method.

Superficially porous silica particle (SPP) C18, 2.7 μm
Pressure = 170 bar

Chromatographic conditions

Column:

Silica monolith: Chromolith® HighResolution RP-18e 100-4.6 mm (1.52022)

FPP: Purospher® STAR RP-18e 3 μm 100-4.6 mm

SPP: Ascentis® Express C18, 2.7 μm 100-4.6 mm

Mobile phase:

A: 100% acetonitrile

B: 20 mM phosphate buffer pH 4.5

Gradient:

Time (min)                  % A                       %B

       0                                20                         80

      12.0                          80                         20

Flow rate:

1.0 mL/min

Detection:

UV 230 nm

Detection cell:

Standard 11 μL

Temperature:

22 ˚C

Injection volume:

2.0 μL

Sample:

1.   Ascorbic acid

2.   4-Hydroxybenzoic acid

3.   Benzoic acid

4.   Sorbic acid

5.   Methyl 4-hydroxy benzoic acid

6.   Methyl 4-hydroxy benzoic acid

7.   Methyl 4-hydroxy benzoic acid

Silica type

High-purity silica (Type B)

Particle size

Monolithic

Macropore size

1.15 μm

Mesopore size

15 nm (150 Å)

Pore volume

1.0 mL/g

Total porosity

> 80%

Surface area

250 m2/g

Surface modification

Octadecylsilane; C18 endcapped

USP classification

L1

Carbon content

15%

Chromolith® RP-8 endcapped and Chromolith® HighResolution RP-8 endcapped Monolithic Silica HPLC Columns

Chromolith® RP-8 endcapped columns provide enhanced retention for hydrophobic compounds compared to the RP-18 columns. With shorter alkyl chains, they offer reduced retention and slightly different selectivity, enabling baseline separations that may not be achievable with RP-18 columns under identical elution conditions.

These columns retain the same benefits as Chromolith® RP-18 columns, including fast throughput, long column lifetime, low matrix sensitivity, and the possibility of pairing columns for maximum performance. Made from high-purity silica, they decrease the impact of trace metals and the n-alkyl chains with high ligand density are fully endcapped to reduce unmodified silanol activity.

Features & Benefits:

  • Superior retention for hydrophobic compounds
  • High throughput at elevated flow rates
  • Flow gradient compatibility
  • Enhanced performance through column coupling
  • Rigid monolithic structure for extended lifetime
  • Lower matrix sensitivity

 

Chromolith® RP-8 endcapped

Chromolith® HighResolution RP-8 endcapped

Silica type

High-purity silica (Type B)

High-purity silica (Type B)

Particle size

Monolithic

Monolithic

Macropore size

2 μm

1.15 µm

Mesopore size

13 nm (130 Å)

15 nm (150 Å)

Pore volume

1.0 mL/g

1.0 mL/g

Total porosity

> 80%

> 80%

Surface area

300 m2/g

250 m2/g

Surface modification

Octlysilane; C8 endcapped

Octlysilane; C8 endcapped

USP classification

L7

L7

Carbon content

11%

11%

Chromolith® CN, NH2, and Diol Monolithic Silica HPLC Columns

Chromolith® columns with polar modifications (CN, NH2 and Diol) are suitable for the separation of polar compounds. These column chemistries can be used for Normal-phase conditions as well as with Reversed phase mobile phases (HILIC -mode).

Cyano columns are generally more polar than traditional alkyl silica columns. The functional groups are highly ordered, reducing steric hindrance for the solute. The modification also allows cation exchange activity, which is higher at neutral pH than in acidic conditions. Chromolith® CN columns are suitable for the separation of alkaloids, oils, flavonoids, glycols, phenols, phthalates, steroids, and sulfonamides.

Chromolith® aminopropyl-modified columns possess medium polarity, between those of bare (normal-phase) silica and reversed-phase silica. Consequently, these columns display hydrophilic as well as hydrophobic properties and can be used under both reversed-phase and normal-phase conditions. These columns are suitable for the separation of anions, organic acids, and carbohydrates (mono and disaccharides, such as fructose, glucose, sucrose, maltose, and lactose).

Chromolith® Diol columns are more versatile than bare silica columns and often offer improved reproducibility. The bonded phase’s hydroxyl groups provide good selectivity without excessive retention. This trait is due to weaker hydrogen bonding with diol groups than with silanols on a bare silica surface. In aqueous phases, the diol phase can effectively shield the silica surface from interacting with proteins. Diol columns are commonly used for the separation of steroids and sterols under normal-phase conditions. Chromolith® Diol columns are suitable for the separation of alcohols, amino acids, carotenoids, oils, glycols, preservatives, proteins, sugars, sulfonamides, and water-soluble vitamins.

 

Chromolith® CN

Chromolith® NH2

Chromolith® Diol

Silica type

High-purity silica (Type B)

High-purity silica (Type B)

High-purity silica (Type B)

Particle size

Monolithic

Monolithic

Monolithic

Macropore size

2 μm

2 μm

2 μm

Mesopore size

13 nm (130 Å)

13 nm (130 Å)

13 nm (130 Å)

Pore volume

1.0 mL/g

1.0 mL/g

1.0 mL/g

Total porosity

> 80%

> 80%

> 80%

Surface area

300 m2/g

300 m2/g

300 m2/g

Surface modification

Cyanosilane

Aminopropyl

Diolsilane

USP classification

L10

L8

L20

Carbon content

6%

5%

9%

Chromolith® Si Monolithic Silica HPLC Columns

Chromolith® Si HPLC columns are specifically designed for normal-phase separations of polar, non-ionic organic molecules. They offer the entire benefits of monolithic silica technology, such as high throughput, prolonged column lifetime, reduced matrix sensitivity, and improved performance via column coupling. These columns are made of high-purity silica and efficiently reduce the influence of trace metals.

Silica type

High-purity

Particle size

Monolithic

Macropore size

2 μm

Mesopore size

13 nm (130 Å)

Pore volume

1.0 mL/g

Total porosity

> 80%

Surface area

300 m2/g

USP classification

L3

Chromolith® CapRod® Monolithic LC Capillary Columns

The Chromolith® CapRod® capillary HPLC columns combine monolithic silica technology with nano-LC sensitivity, increasing productivity for high-throughput and high-sensitivity proteomics LC applications. These columns are specifically intended for the efficient and selective separation of peptides and protein digests. The sol-gel method utilized to produce the columns is especially favorable for capillary and nano-LC applications, as it improves separation performance and sensitivity.

Unlike conventional columns, Chromolith® CapRod® capillaries are not limited by column length and can be bent to a certain degree in order to accommodate different LC layouts and instruments. These monolithic capillary columns are compatible with a variety of nano or capillary LC systems and offer improved efficiency and performance when connected to mass spectrometers, both on-line (ESI, nanospray) and off-line (MALDI). These columns can operate at higher flow rates without any degradation in performance or issues related to column back pressure. Flow rates can be significantly increased while maintaining resolution, allowing separations to be performed at 1-3 μL/min, in contrast to the 200-400 μL/min typically required for conventional media in a standard 100 μm LC capillary column.

CapRod® columns have a dual-pore structure with large macropores (~2 µm) and small mesopores (13 nm), resulting in a highly porous monolithic rod of pure silica. The macropores allow for quick eluent flow, considerably lowering separation times, but the mesopores provide a fine-pore structure within the capillary, offering a vast surface area for effective adsorption of target molecules.

Chromolith® CapRod® columns come in a variety of internal diameters (50 μm, 100 μm, and 200 μm), bonded phases (C8, C18), pore shapes (standard and high resolution), and lengths (5, 15, and 30 cm). Each column comes with sleeves and standard 1/16" PEEK fittings for connecting directly to a UV detector or mass spectrometer. Trapping capillaries are also available, designed to protect the separation column and enhance efficiency when working with complex biological samples.

Features & Benefits

  • Superior performance with optimal resolution (narrow peak widths)
  • Enhanced sample throughput for maximum productivity
  • Greater efficiency due to prolonged column lifetime
  • Higher flow rates thanks to unique bimodal pore structure
  • Greater flexibility for best fit to any LC configuration and instrument

Sorbent characteristics

Monolithic silica gel

Column inner diameter

0.05 (50 μm), 0.1 mm (100 μm) and 0.2 mm (200 μm)

Column length

150 mm, 300 mm

Surface modification

RP-8 endcapped, RP-18 endcapped

Macropore size

2 μm (1 μm for “HighResolution” products)

Mesopore size

13 nm

Surface area

300 m2/g

Chromolith® HPLC Column Coupler

The Chromolith® HPLC column coupler enables the combination of several monolithic columns to improve separation efficiency by increasing the potential plate count beyond that of particle columns, while keeping pressure below the system limit. This enhances column performance, making it excellent for overcoming crucial separation difficulties and handling complicated mixes that were previously unsuitable for separation.

Table below shows a comparison between Chromolith® HPLC columns and particulate columns. The use of only two Chromolith® Performance RP-18 endcapped columns results in a separation efficiency of 19,000 theoretical plates per column, which is often the maximum for particle columns.

Comparison of Chromolith® HPLC Columns and Particulate Columns

Column

Length [mm]

Pressure [bar]

Plate number per column [Anthracene]

Chromolith® Performance 1x

100

30

10,000

Chromolith® Performance 2x

200

60

19,000

Chromolith® Performance 3x

300

90

27,000

Chromolith® Performance 4x

400

120

35,000

Chromolith® Performance 5x

500

150

41,000

Particulate column
(5 μm)

250

220

18,500

Particulate column (3.5 μm)

150

400

19,000

Chromolith® Guard Cartridges and Kit

Chromolith® guard cartridges and kits offer optimum protection of analytical columns against chemical or mechanical contamination, significantly extending column lifetime. The guard cartridges are chemically modified with hydrophobic n-octadecyl (C18) groups on a monolithic silica rod, making them suitable for reversed-phase chromatography.

Guard Cartridges

Chromolith® guard cartridges, available in 5 and 10 mm lengths, are easy-to-use and provide the benefits of monolithic technology. These guard columns are also excellent at protecting classical packed columns and should be changed on a regular basis to prevent impurities from building up.

Guard Cartridge Starter Kit

The Chromolith® guard cartridge package comprises a guard cartridge holder and three guard cartridges, providing a comprehensive solution for extending column life.

Chromolith® SemiPrep HPLC Columns

Chromolith® SemiPrep HPLC columns are ideal for scaling up from analytical to semi-preparative separations, providing faster throughput at lower pressure than 5 μm-packed semi-prep columns. They are highly effective at separating non-polar basic and acidic compounds, as well as peptides.

With a 10 mm internal diameter, they are an efficient alternative to particle columns with diameters of 10 mm and 21.2 mm, giving selectivity comparable to RP-18 endcapped reversed-phase columns. The rugged monolithic silica structure, identical to Chromolith® analytical columns (4.6 mm I.D.), ensures a long column lifetime. The 2 μm macropores reduce separation time, while the 13 nm mesopores offer a large surface area for adsorption.

Features & Benefits:

  • Direct scale-up from analytical to semi-prep
  • Faster throughput at lower operating pressure than 5 μm columns
  • Sharp separations, even with high sample loads
  • Extended lifetime due to robust monolithic structure
  • LC/MS optimized with minimal column bleeding
  • High performance at various flow rates
  • Ideal alternative to 10 mm and 21.2 mm I.D. particulate columns

The Chromolith® HPLC and UHPLC monolithic silica columns are cladded in inert PEEK (polyetheretherketone) polymeric material and can be connected directly to HPLC, UHPLC or UPLC system as a “ready to use” column.

chromolith-column

Chromolith column

Chromolith® Columns for Small Molecule Separations - I

Length (mm) I.D. (mm)RP-18eHR RP-18eRP-8eHR RP-8ePhenyl
Chromolith® HPLC Column [1 unit]
25x4.61.51463.00011.52020.0001  1.52056.0001
25x31.52003.0001    
25x21.52014.00011.52320.0001   
50x4.61.51450.00011.52021.0001  1.52057.0001
50x31.52002.0001    
50x21.52007.00011.52321.0001   
100x4.61.02129.00011.52022.00011.51468.00011.52064.00011.52058.0001
100x31.52001.0001    
100x21.52006.00011.52322.0001   
150x4.6 1.52023.0001   
100x101.52016.0001    
100x251.25252.0001    
Validation Kits [3 Chromolith® HPLC cartidges from 3 different sorbent batches]
50x21.52062.0001    
100x4.61.51466.00011.52019.0001   
100x31.52063.0001    
100x101.52036.0001    
Chromolith® Guard cartidges [3 units]
5x4.61.51451.00011.52025.00011.52013.0001 1.52059.0001
10x4.61.51452.0001    
5x31.52005.0001    
5x21.52009.00011.52325.0001   
Chromolith® Guard cartidge Set [1 starter kit  with holder and 3 guard cartridges]
5x21.52008.0001    
5x31.52004.0001    

Chromolith® Columns for Small Molecule Separations - II

Length (mm) I.D.(mm)CNDiolNH2Si
Chromolith® HPLC Column [1 unit]
25x4.61.52046.00011.53170.00011.52026.0001 
25x3    
25x2    
50x4.61.52047.00011.53171.00011.52027.0001 
50x3    
50x2    
100x4.61.52048.00011.53172.00011.52028.00011.51465.0001
100x3    
100x2    
150x4.6    
100x10   1.52015.0001
100x25   1.25251.0001
Validation Kits [3 Chromolith® HPLC cartidges from 3 different sorbent batches]
50x2    
100x4.6    
100x3    
100x10   1.52035.0001
Chromolith® Guard cartidges [3 units]
5x4.61.52050.00011.53175.00011.52030.00011.52011.0001
10x4.6    
5x3    
5x2    
Chromolith® Guard cartidge Set [1 starter kit  with holder and 3 guard cartridges]
5x2    
5x3    
Chromolith® Holder
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