Optimum Bed Density (OBD) Technology

Lifetime of a preparative column is no longer a random event. Scientists like you, have come to rely on the high purity and recovery obtained with Waters Prep OBD Columns.

Extensive development of the column hardware and packing process has led to predictable uniform density throughout the column to maximize mechanical stability. Extended column lifetimes and high mass loading capacity have led to increased productivity.

Scientists select OBD Prep Columns for robustness, predictabable perfomance, and ease of scaling from analytical to prep.

Click here if you are looking for SFC Columns

OBD Prep Column Design

The OBD Preparative Column is designed to incorporate a pair of specially-designed distributors and chemically-inert seals made to prevent leaks at high operating pressures.

Introduction to Purification

Laboratory-scale HPLC purification presents many challenges. Watch this recorded presentation to help you get started. Watch Now

Preparative Chromatography: Considerations for Column Selection

Explore Techniques to Transfer UPLC Methods to Preparative HPLC

The OBD Preparative Column is designed to incorporate a pair of specially-designed distributors and chemically-inert seals made to prevent leaks at high operating pressures.

Waters LC Prep Instruments

Preparative-scale HPLC chromatography plays a critical role in applications where compounds must be synthesized, identified, isolated, purified, characterized, screened, and tested. The Waters suite of HPLC purification solutions offer scalable configurations, from semi-automated modular systems to fully automated MS-directed systems, whether you want the specificity of mass-directed purification or inclusiveness of a UV system. 

Scalable prep systems, from simple low-pressure mixing systems for purifying a few samples a day, to the AutoPurification HPLC or HPLC-MS System for high-throughput fraction collection from hundreds of samples, to batch Supercritical Fluid Chromatography (SFC) systems for the purification of large amounts of single samples. Learn more

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Prep Calculator

Waters provides convenient scale-up calculation tools for mass load scaling, gradient scaling with appropriate flow rate scale-up and predicting volume consumption, split flow ratios for those using mass spectrometer driven chromatography and focused gradient UPLC to preparative method transfer. Note: Scale-up calculations are carried out using the equations show on the Preparative OBD Columns Wall Chart.

To try this tool, visit www.waters.com/prepcalculator or select from the appropriate calculator links below:

• Analytical to Prep Gradient Calculator: This calculator will calculate the preparative method conditions, determine solvent usage, show the preparative method gradient profile, and will assist in scaling up injection volume and preparative mass load based on the analytical data, along with equilibration and total cycle times.

• Tubing Backpressure and Splitter Calculator: This calculator will estimate tubing backpressure, from tubing I.D., tubing length, flow rate and mobile phase. To aid with passive flow splitting for multi-detection and/or fraction collection, this calculator will also aid with determining tubing I.D. and length required.

• UPLC to Focused Gradient Calculator: With results from analytical screening including target peak retention time, this calculator determines focused gradient conditions, along with both starting and focused gradient profiles.
• Column Backpressure and Splitter Calculator: With analytical and preparative column parameters and screening method conditions including analytical mass load and injection volume, this calculator scales up the mass load, injection volume and determines column backpressure.

Mass Loading

Many factors affect the mass capacity of preparative columns.  The listed capacities represent an average estimate:

• Higher for strongly retained material
• Higher for simple mixtures
• Lower where higher resolution is required
• Very strongly dependent on loading conditions

For more detailed instructions on scaling-up, download our Preparative OBD Columns Wall Chart or visit our Prep Calculator.

Isolation and Purification of Peptides

The isolation and purification of peptides has been difficult because of unpredictable separations, short column lifetime, and lack of scalability. Peptide Separation Technology Columns provide a stable surface chemistry that can be used for most peptides. Scaling the optimized separation requires identical column chemistry and performance across a range of column dimensions. When the OBD Preparative Column design is coupled with the stable surface chemistry of Peptide Separation Technology Columns in a range of particle sizes, the process of peptide isolation and purification becomes more efficient, and overall costs are reduced.

Practical Approaches to Peptide Isolation

Application Notebook: Analyses of Biotherapeutic Peptides

Preparative Guard Cartridges and Holders

The use of preparative guards will greatly extend the preparative column lifetimes. These preparative guard holder and cartridge assemblies are available in 10mm length in four different I.D.'s including, 7.8, 10, 19, and 30 mm to protect Waters premium OBD Preparative Columns with the same internal diameter. Below is a quick way to search our various brands for the cartridge guards and appropriate holders.

7.8 x 10 mm cartridges and 7.8 x 10 mm Cartridge Holder
10 x 10 mm cartridges and 10 x 10 mm Cartridge Holder
19 x 10 mm cartridges and 19 x 10 mm Cartridge Holder
30 x 10 mm cartridges and 30 x 10 mm Cartridge Holder

Guard columns are easily installed ahead of the preparative column and provide superior protection.

System Volume

System volume is important in scaling separations because it creates an isocratic hold at the start of every run. This hold is often several column volumes on a small scale, but a fraction of the volume of a prep column. Compensation for this volume must be included in planning a scaling experiment to avoid distorting the chromatography.

Recommended Method for Measurement

1. Remove column.
2. Use Acetonitrile as mobile phase A, and Acetonitrile with 0.05 mg/mL uracil as mobile phase B (eliminates non-additive mixing and viscosity problems).
3. Set UV detector at 254 nm.
4. Use the flow rate in the original method and the intended flow rate on the target instrument.
5. Collect 100% A baseline for 5 minutes.
6. Program a step change at 5 minutes to 100% B, and collect data for an additional 5 minutes.
7. Measure absorbance difference between 100% A and 100% B.
8. Measure time at 50% of that absorbance difference.
9. Calculate time difference between start of step and 50% point.
10. Multiply time difference by flow rate

Preparative Standards

Preparative Chromatography Mix Standard

The Preparative Chromatography Mix Standard is a specially formulated mix for the preparative or purification system. The Preparative Chromatography Mix Standard allows the user to evaluate and benchmark their chromatography prep or purification system with UV or MS before analysis of critical material. The Preparative Chromatography Standard includes a void marker, neutral, acidic and basic compounds. It can be used with a variety of column chemistries and dimensions, and system hardware. Buy now

AutoPurification System Standard
The AutoPurification System Standard tests the performance of fraction collectors for both UV-directed and MS-directed systems performing reversed-phase separations. The 3 dye test mix can be used on all purification systems with fraction collection. Buy now