Ultra HPLC

Restek Ultra IBD is a polar-embedded reversed-phase column engineered for enhanced retention and selectivity of acids and other polar compounds. Designed with a proprietary polar functional group embedded within an alkyl chain (L68 classification), Ultra IBD acts as a strong hydrogen-bonding phase while maintaining traditional reversed-phase characteristics.

The high-purity, type-B silica support minimizes secondary activity and enables high-density bonding, delivering symmetrical peak shape for strongly basic analytes. Ultra IBD is fully compatible with 100% aqueous mobile phases and can also be operated under reversed-phase or HILIC-like conditions to retain highly polar or ionic compounds in organic-rich environments.

Key Characteristics

• Stationary Phase Category: Polar-embedded alkyl (L68)
• Ligand Type: Proprietary polar functional embedded alkyl
• Particle Size: 3 µm or 5 µm, spherical
• Pore Size: 100 Å
• Carbon Load: 12%
• End-Capped: No
• Surface Area: 300 m²/g
• pH Range: 2.5–8
• Maximum Temperature: 80 °C

Ideal For

• Retention of acidic and polar analytes
• Improved peak shape for basic compounds
• Methods requiring 100% aqueous mobile phases
• Mixed-mode selectivity without dedicated mixed-mode chemistry

Restek Ultra Biphenyl delivers enhanced aromatic and π–π interaction selectivity compared to conventional phenyl phases. Offering greater dispersion than standard phenyl columns and higher polarizability than phenyl-hexyl chemistries, this phase provides increased retention and improved resolution—particularly for dipolar, unsaturated, and conjugated analytes.

These heightened interaction mechanisms result in improved orthogonal selectivity when using methanol mobile phases, making Ultra Biphenyl especially valuable for LC-MS workflows that require increased sensitivity and distinct separation profiles.

Phase Characteristics

• Stationary Phase Category: Phenyl (L11)
• Ligand Type: Unique Biphenyl
• Particle Size: 3 µm or 5 µm, spherical
• Pore Size: 100 Å
• Carbon Load: 15%
• End-Capped: Yes
• Surface Area: 300 m²/g
• pH Range: 2.5–8
• Maximum Temperature: 80 °C

Ideal For

• Aromatic and conjugated compound separations
• Enhanced π–π interaction selectivity
• Improved retention of dipolar and unsaturated solutes
• LC-MS methods using methanol mobile phases

Restek Ultra PFP Propyl provides unique selectivity for charged bases, electronegative compounds, and amine-containing analytes. Built on high-purity type-B silica with high-density bonding, this fluorinated phenyl phase delivers consistent and reliable HPLC performance across a broad range of applications.

Unlike conventional cyano phases, Ultra PFP Propyl is highly amenable to LC-MS workflows due to its reliable performance under acidic mobile phase conditions. The pentafluorophenyl propyl ligand promotes multiple interaction mechanisms—including π–π, dipole–dipole, and hydrogen bonding—enhancing retention and orthogonal selectivity.

This versatile column is also compatible with highly aqueous mobile phases and can be used in HILIC-like separations when increased polarity retention is required.

Phase Characteristics

• Stationary Phase Category: Fluorophenyl Propyl (L43)
• Ligand Type: Pentafluorophenyl propyl
• Particle Size: 3 µm or 5 µm, spherical
• Pore Size: 100 Å
• Carbon Load: 11%
• End-Capped: Yes
• Surface Area: 300 m²/g
• pH Range: 2.5–8
• Maximum Temperature: 80 °C

Ideal For

• Charged and basic analytes
• Electronegative and halogenated compounds
• Amine-containing molecules
• LC-MS methods with acidic mobile phases
• Highly aqueous or mixed-mode-like separations

Restek Ultra C18 is a general-purpose, monomeric octadecylsilane (L1) reversed-phase column designed for reliable separations across a broad range of analytes. Built on high-purity, type-B silica with high-density bonding, Ultra C18 delivers consistent retention, symmetrical peak shape, and dependable reproducibility for routine HPLC workflows.

This versatile phase is suitable for compounds ranging from acidic to slightly basic, making it an ideal starting point for method development and a dependable option for quality control and high-throughput analytical testing.

Phase Characteristics

• Stationary Phase Category: C18, Octadecylsilane (L1)
• Ligand Type: Monomeric C18
• Particle Size: 3 µm or 5 µm, spherical
• Pore Size: 100 Å
• Carbon Load: 20%
• End-Capped: Yes
• Surface Area: 300 m²/g
• pH Range: 2.5–8
• Maximum Temperature: 80 °C

Ideal For

• General-purpose reversed-phase separations
• Acidic to slightly basic analytes
• Routine HPLC and QC methods
• Method development starting point

Restek Ultra C4 is a stable, monomeric butylsilane (L26) reversed-phase column designed for applications requiring reduced hydrophobic retention compared to C18 or C8 phases. Built on high-purity, type-B silica with high bonding coverage and effective base deactivation, Ultra C4 delivers consistent peak shape and reliable performance across a broad range of analytes.

With lower carbon loading than longer-chain phases, Ultra C4 provides moderated retention, making it well suited for large molecules, peptides, proteins, and compounds that may be overly retained on C18 columns.

Phase Characteristics

• Stationary Phase Category: C4, Butylsilane (L26)
• Ligand Type: Monomeric C4
• Particle Size: 3 µm or 5 µm, spherical
• Pore Size: 100 Å
• Carbon Load: 9%
• End-Capped: Yes
• Surface Area: 300 m²/g
• pH Range: 2.5–8
• Maximum Temperature: 80 °C

Ideal For

• Peptides and protein separations
• Large or moderately hydrophobic analytes
• Applications requiring less retention than C18 or C8
• Reversed-phase methods needing balanced hydrophobic interaction

Restek Ultra C8 is a conventional monomeric octylsilane (L7) reversed-phase column that offers shorter alkyl chain chemistry for moderated hydrophobic retention compared to C18 phases. Built on high-purity, type-B silica with high-density bonding, Ultra C8 delivers reliable performance and improved basic peak shape in many analytical methods.

This general-purpose phase is well suited for analytes ranging from acidic to slightly basic and provides an excellent balance between retention strength and resolution. Ultra C8 is ideal when C18 retention is excessive or when faster elution is desired without sacrificing chromatographic efficiency.

Phase Characteristics

• Stationary Phase Category: C8, Octylsilane (L7)
• Ligand Type: Monomeric C8
• Particle Size: 3 µm or 5 µm, spherical
• Pore Size: 100 Å
• Carbon Load: 12%
• End-Capped: Yes
• Surface Area: 300 m²/g
• pH Range: 2.5–8
• Maximum Temperature: 80 °C

Ideal For

• General-purpose reversed-phase separations
• Applications requiring less retention than C18
• Improved peak shape for basic analytes
• Faster run times with balanced resolution

Restek Ultra Silica features base-deactivated, high-purity spherical silica designed for normal-phase and HILIC separations. As a bare silica (L3) phase, it provides strong polar interactions and is well suited for analytes that require retention mechanisms beyond traditional reversed-phase chemistry.

Manufactured from type-B silica with controlled surface activity and high surface area, Ultra Silica delivers consistent performance for polar compound analysis, offering dependable selectivity and reproducibility across a wide range of HPLC applications.

Phase Characteristics

• Stationary Phase Category: Bare Silica (L3)
• Ligand Type: None (unbonded silica)
• Particle Size: 3 µm or 5 µm, spherical
• Pore Size: 100 Å
• Carbon Load: N/A
• End-Capped: N/A
• Surface Area: 300 m²/g
• pH Range: 2.5–8
• Maximum Temperature: 80 °C

Ideal For

• Normal-phase separations
• HILIC methods for polar analytes
• Strong polar interaction selectivity
• Alternative selectivity to reversed-phase chemistry

Restek Ultra Amino is a general-purpose aminopropylsilane (L8) phase designed for reproducible retention and high efficiency in normal-phase and HILIC separations. Built on high-purity, type-B spherical silica with high-density bonding, this phase delivers reliable performance for polar compound analysis.

Ultra Amino is especially well suited for the analysis of simple sugars and other polar analytes that benefit from hydrogen bonding and weak ion-exchange interactions. Its balanced surface chemistry provides dependable selectivity across a broad range of HPLC applications.

Phase Characteristics

• Stationary Phase Category: Amino (L8)
• Ligand Type: Aminopropylsilane
• Particle Size: 3 µm or 5 µm, spherical
• Pore Size: 100 Å
• Carbon Load: 2%
• End-Capped: No
• Surface Area: 300 m²/g
• pH Range: 2.5–8
• Maximum Temperature: 80 °C

Ideal For

• Normal-phase separations
• HILIC analysis of polar compounds
• Simple sugar and carbohydrate analysis
• Applications requiring weak ion-exchange characteristics

Restek Ultra C1 is an exceptionally stable trimethylsilane (L13) reversed-phase column that provides the lowest hydrophobic retention within the Ultra reversed-phase family. Built on high-purity, type-B spherical silica with high-density bonding and effective base deactivation, Ultra C1 delivers reliable performance with minimal retention strength.

As the least-retentive hydrocarbon phase in the Ultra lineup, C1 is ideal for very hydrophobic compounds that may be excessively retained on C18 or C8 phases, or when rapid elution and shortened run times are required.

Phase Characteristics

• Stationary Phase Category: Trimethylsilane (L13)
• Ligand Type: Monomeric C1
• Particle Size: 3 µm or 5 µm, spherical
• Pore Size: 100 Å
• Carbon Load: 5%
• End-Capped: Yes
• Surface Area: 300 m²/g
• pH Range: 2.5–8
• Maximum Temperature: 80 °C

Ideal For

• Very hydrophobic analytes
• Applications requiring minimal retention
• Fast gradient or short run-time methods
• Situations where C18 or C8 retention is excessive

Restek Ultra Aromax is a unique reversed-phase phenyl (L11) column engineered for extreme retention and selectivity of aromatic and unsaturated compounds. Built on high-purity, type-B spherical silica with high-density bonding, Ultra Aromax provides enhanced interaction strength compared to conventional phenyl chemistries.

This phase is an excellent alternative to biphenyl columns when increased retention is required. Ultra Aromax delivers strong π–π interactions and enhanced aromatic selectivity, making it especially valuable for gradient LC-MS methods where traditional reversed-phase columns do not provide adequate retention or resolution.

Phase Characteristics

• Stationary Phase Category: Phenyl (L11)
• Ligand Type: Proprietary phenyl ligand
• Particle Size: 3 µm or 5 µm, spherical
• Pore Size: 100 Å
• Carbon Load: 17%
• End-Capped: Yes
• Surface Area: 300 m²/g
• pH Range: 2.5–8
• Maximum Temperature: 80 °C

Ideal For

• Aromatic and unsaturated analytes
• Enhanced π–π interaction selectivity
• Applications requiring greater retention than biphenyl phases
• Gradient LC-MS methods with insufficient retention on conventional phases

Restek Ultra Carbamate was developed specifically for fast and reliable carbamate pesticide analysis. This unique packing separates 10 target carbamates in just 5 minutes, with a total cycle time of 8 minutes—dramatically increasing laboratory throughput compared to general-purpose C18 columns.

Compatible with both fluorescence and LC-MS detection, Ultra Carbamate can process up to eight samples per hour, versus fewer than two samples per hour on conventional C18 phases. The significantly shorter run time reduces solvent consumption and lowers waste disposal costs, improving overall laboratory efficiency.

Phase Characteristics

• Application-Specific: Carbamate pesticide analysis
• Particle Size: 3 µm or 5 µm, spherical
• Pore Size: 100 Å
• Carbon Load: Proprietary
• Surface Area: 300 m²/g
• pH Range: 2.5–8
• Maximum Temperature: 80 °C

Performance Advantages

• Separates 10 carbamates in 5 minutes
• 8-minute total cycle time
• Compatible with fluorescence and LC-MS detection
• Up to 8 samples per hour throughput
• Reduced solvent usage and waste disposal costs

Note: For post-column derivatization/fluorescence detection using a 4.6 mm ID column, total system dead volume—including the post-column reactor—must be less than 650 µL. For standard post-column reactor systems, a 250 mm × 4.6 mm, 5 µm column is recommended. Contact Chrom Tech for technical guidance and configuration assistance.

Restek Ultra Aqueous C18 is a rugged, polar-modified reversed-phase column engineered to retain a broader range of solutes than conventional C18 phases. Built on high-purity, type-B silica with functionally bonded, proprietary modified C18 chemistry, this phase delivers balanced retention and enhanced compatibility with highly aqueous mobile phases.

Ultra Aqueous C18 is ideal for multicomponent LC-MS analyses and general-purpose methods that require reproducibility across diverse mobile phase conditions—even up to 100% aqueous. When used with gradient elution, it helps eliminate the common issue of polar compounds eluting near the column void time.

Phase Characteristics

• Stationary Phase Category: Modified C18 (L1)
• Ligand Type: Proprietary polar-modified and functionally bonded C18
• Particle Size: 3 µm or 5 µm, spherical
• Pore Size: 100 Å
• Carbon Load: 15%
• End-Capped: No
• Surface Area: 300 m²/g
• pH Range: 2.5–8
• Maximum Temperature: 80 °C

Ideal For

• Highly aqueous mobile phase conditions (including 100% aqueous)
• Multicomponent LC-MS analyses
• Improved retention of polar analytes
• Gradient methods requiring broader retention profiles