Centrifugal partition chromatography: equipment and solutions
What is CPC?
Centrifugal partition chromatography – CPC – is a separation technique utilizing the different partition coefficients of compounds between two immiscible liquids. CPC uses the physics of traditional liquid-liquid extraction but gives the results typical for adsorption chromatography as peaks and fractions.
CPC does not necessarily replace the traditional extraction or chromatography but is a very good economical alternative solution for crude separation of the mixture into several fractions. It can also be a viable option when the sensitive material reacts with solid stationary phases like silica and the only solution is liquid-liquid technique.
CPC physical basics
CPC does not use silica or any other solid sorbents, while the stationary phase is always a liquid. The stationary phase is retained within the separation cell by a strong centrifugal force, and mobile phase is constantly pumped through the stationary phase. During the separation process, the compounds are distributed between the stationary and mobile phase in accordance with their partition coefficients. The compounds with lower partition coefficients are eluted first followed by the other compounds with higher partition coefficients.
Technically, the extraction takes place inside small chambers (called “cells”) connected in series, which can be corresponded to classical chromatography columns connected one after the other. To ensure the retention of the stationary phase, the cells are mounted on the constantly spinning rotor. The centrifugal force ensures the phase border between the liquids with different density and helps the stationary phase not to be mixed and/or pumped out with the mobile phase.
The solvents coming out of the CPC are continuously analyzed and a chromatogram is compiled in real-time for monitoring using a UV‑VIS detector. Other methods (refractive index, conductivity, light scattering, optical rotation) can be considered for detection. Based on the chromatogram, the output is fractionated into several collecting vessels.
Very important conditions for the successful CPC separation are:
- stationary and mobile phase should be immiscible liquids, for example:
hexane and water, heptane and methanol, hexane and acetonitrile - the separated components should have a good solubility in one phase and limited (but not zero) solubility in other phase
CPC instruments and equipment
The components of the typical CPC system are almost the same as components of preparative HPLC but the separation column is replaced by the CPC unit. The complete CPC system includes:
Pilot scale CPC
- Quaternary gradient HPLC pump: channel 1 = mobile phase, channel 2 = stationary phase, channel 3 = mixture
- CPC unit
- Detector
- Fraction collector
- PC with software
Industrial CPC
- Solvent box with 4-way gradient valve and built-in PC (compliant software pre-installed)
- Preparative scale quaternary piston pump
- CPC unit
- Detector
- 10-position fractionation valve (fraction vessels are optional)
- Electrical control cabinet
Key advantages
- No expensive and sensitive silica
The CPC technique does not require any silica since it only uses liquids as the stationary phase.
- No need of ultra-pure solvents
While the traditional preparative chromatography is very sensitive to the impurities of the mobile phase, the CPC may use the standard industrial/technical grade solvents instead of HPLC grade ones.
- Short cycle time
Compared to traditional preparative chromatography, the retention times are shorter when using CPC. As a result, more material can be separated within the same time.
- Easy recycling and environmental efficiency
Both the mobile and the stationary phase can be recycled up to 95 %.
- No problem with highly viscous media
The highly viscous liquids are easily pumped through the liquid stationary phase, resulting no such high backpressure as with solid sorbents.
- Easy scale-up
Normally, the other chromatographic techniques require a lot of parameters to be considered when scaling up the separation (column diameter, column length, particle size, pressure, flow rate etc.). Instead, the scale-up of a CPC method requires just the proportional increase of the stationary phase volume and mobile phase flow rate.
Applications
CPC is not the substitution, but a very good alternative to other chromatographic techniques. CPC is a perfect tool for the tasks where the traditional preparative chromatography consumes a lot of solvent and expensive silica or has the risk of irreversible damage to the sensitive input material.
CPC is excellent for:
- crude separation of components after chemical synthesis
- crude separation of components after solid-liquid extraction (for example, production of natural extracts)
- removal of complex matrices
- concentration increase of target compounds
Pharmaceutical applications
- Isolation of an antibiotic oligopeptide
- Polishing of an anticancer API
- Isolation of mitragynine
- Isolation of plasma proteins
- Polishing of a steroid API
- Isolation of digoxin from a natural extract
- Preparative separation of diastereomers
- Isolation of 10 DAB-III
Cosmetics and fragrances
- Preparative separation of epimer diterpenes without chiral additives/selectors
Food and beverages
- Separation of vitamin E isomers
- Preparative separation of ecdysteroids
- Purification of quercetin glycosides
CPC solutions of RotaChrom
rCPC
Pilot-scale CPC platform
- To execute pilot‑scale purification tasks within a laboratory environment
- Ideal for all batch sizes, smaller or larger, or campaign type of research work, and continuous batch production
- User‑friendly operation
- Integrated solvent system
- Available for pharma GMP environment and in URS‑compliant equipment design
- 2,000 mL
- 100 individual cells
- Loading capacity: up to 150 g
- Usual runtime: 18 … 35 minutes
- Nominal flow rate: 250 mL/min
- Throughput: up to 2 kg/day
- Continuous batch operation
GMP rCPC
GMP‑compliant pilot‑scale CPC platform
- GMP‑compliant pilot‑scale CPC platform
- Designed to adhere to pharma GMP regulations
- Can be used for API‑grade compound production and pilot‑scale purification, as well as for research tasks in a pharmaceutical environment
- Comes with material certification and traceability for all parts
- Own cleaning validation and cleaning process
- Every aspect of the unit is tailored and executed exactly to the User Requirement Specifications (URS)
- 21 CFR Part 11 software
- 2,000 mL
- Loading capacity: up to 150 g
- Usual runtime: 18 … 35 minutes
- Nominal flow rate: 250 mL/min
- Throughput: up to 2 kg/day
- Robust and reliable
Continuous CPC
Pilot‑scale continuous operation CPC
- Purification and polishing solution for difficult matrices, where the difference between individual constituents is negligible
- Enhances the resolving power and further reduces the relative cost of consumables using two rotors working hand‑in‑hand under a single control unit
- Enables a simulated-moving-bed type of chromatographic solution without a delicate and complicated fluid system
- 2,000 … 12,000 mL
- Interchangeable rotors
- Dual rotor design
- Continuous injection
- Increased throughput
- Higher resolution
- One control unit for both rotors
iCPC
Industrial‑scale CPC platform
- Largest serialized CPC instrument in the world, designed for industrial‑scale purification projects
- The most cost‑effective industrial‑scale chromatography platform available on the market
- Capacity to process hundreds of kilograms of crude input material per month
- Controlled by a PLC unit, which enables system finetuning and the aligned functioning of multiple devices
- 20,000 mL
- 75 individual cells
- Loading capacity: up to 1.2 kg
- Usual runtime: 18 … 35 minutes
- Nominal flow rate: 2.5 L/min
- Throughput: up to 20 kg/day
- Scale‑up: 8 … 10x rCPC
pCPC
Industrial‑scale CPC with automated solvent preparation and recovery systems
- Industrial‑scale CPC with automated solvent preparation and recovery systems
- Combination of iCPC and solvent preparation, recovery and regeneration
- Proprietary automated biphasic solvent system preparation platform, providing a flexible and continuous feed to iCPC instrument
- Automate complete purification process and make products that meet all standards
- Can be operated in a hazardous environment in compliance with existing regulatory requirements
- Process flow and layout can be tailored to customer needs before installation
- 20,000 mL
- Loading capacity: up to 1.2 kg
- Usual runtime: 18 … 35 minutes
- Nominal flow rate: 2.5 L/min
- Throughput: up to 20 kg/day
- Scale‑up: 8 … 10x rCPC
- Optimized solvent system: preparation, recycling, recirculation
Customer support by RotaChrom Technologies and STOPROCESS Verfahrenstechnik
Our scope of services includes:
- Feasibility and rentability studies
We make the checking the overall possibility of the separation using CPC technique and evaluation of the operating costs by the CPC separation
- Rental equipment
For the customers in Europe, we offer a rental service of the CPC platforms – either as standalone modules to be combined with existing prep HPLC, or as complete turnkey solution.
- Combination with other processing steps
We have considerable experience with various upstream and downstream processing techniques: chemical reactions, distillation, solid-liquid extraction, evaporation, crystallization etc. It helps our customers reach the maximum performance of the CPC units.
- Installation
We provide correct installation at the customer’s facilities, considering environmental restrictions and occupational safety regulations, also trainings of the personnel.
- Method development, scale‑up
At the customer’s facilities, we are available for the on‑site method development until the customer gets the desirable result. Online support and consultancy are available as well.
- Supplement to the existing prep HPLC systems
Pilot‑scale CPC modules may be easily combined with the existing prep HPLC installations at the pilot labs, especially under control of Clarity software (Knauer, Agilent, ECOM etc.)
- DQ/IQ/OQ/PV
We develop the full package of the validation documentation and make all required tests according to the cGMP rules.
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