I. Overview
In fields such as drug discovery, natural product extraction, and peptide synthesis, efficiently obtaining high-purity compounds remains a core bottleneck. Fully automated preparative liquid chromatography systems integrate automatic injection, gradient elution, online detection, and fraction collection, and have gradually replaced traditional column chromatography. Compared with analytical HPLC, preparative chromatography features larger flow rates, higher loading capacity, and automated fraction collection, enabling 24-hour continuous purification. With 30 years of experience in liquid chromatography, Elite provides a complete product line from semi-preparative to industrial preparative systems.
II. Selection Guide
For microgram- to milligram-scale purification, a semi-preparative system is sufficient. For gram- to ten-gram-scale pilot purification, higher flow rates and larger column diameters are required. Elite's products cover a complete flow rate gradient: the 3140AP semi-preparative system with a flow range of 0.1–40.00 mL/min is suitable for laboratory-scale trials; the EClassical 3500/3700 with 0.01–100.00 mL/min meets microgram- to gram-scale needs; and the Elite IPC-50 series is designed for ten-gram to kilogram-scale production.
The solvent delivery pump is the heart of the system. Key selection criteria include flow accuracy, flow stability, and gradient precision. The Elite P3500 high-pressure constant-flow pump adopts proprietary plunger drive technology, with flow accuracy within ±1.0% and flow stability RSD ≤ 0.3%, maintaining low pulsation over a wide flow range. The intelligent multi-volume gradient mixer ensures precise reproducibility of mobile phase ratios during complex gradient elution.
Preparative detectors must qualitatively identify target peaks and precisely trigger fraction collection. Dual-wavelength or full-spectrum detectors are preferred. The EClassical 3150 is equipped with the D3150 dual-wavelength UV-Vis detector; the EClassical 3500/3700 features a full-spectrum detector with a wavelength range of 190–700 nm and baseline noise as low as ±0.5×10⁻⁵ AU. The S3320 automatic injection-fraction collector integrates injection and collection, with a tray design supporting free switching between injection and collection, and offers both time-window and threshold collection modes, effectively avoiding cross-contamination.
Consider expandability for multi-detector coupling, autosampler upgrades, and fraction collector compatibility. Pharmaceutical users should also evaluate GMP/GLP compliance. The Elite Kromstation chromatography workstation provides audit trails, user permission management, and electronic signatures, meeting data integrity regulatory requirements and supporting modular expansion.
III. Typical Applications
Peptides have high sequence similarity and complex by-products, making purification challenging. The EClassical 3500/3700 combined with the S3320 automatic injection-fraction collector and Elite peptide-specific columns can effectively separate deletion peptides, truncated peptides, and epimers, achieving purity above 99%. Automated continuous operation supports uninterrupted purification of multiple batches, improving throughput and yield.
Natural products have complex compositions and low target content. Elite preparative systems can be flexibly configured for normal-phase, reversed-phase, or gel filtration modes, separating components of different polarities via gradient elution. From extracting active monomers from Chinese herbal medicines and separating flavonoids and alkaloids to large-scale preparation of reference standards, the system operates stably.
Addressing diverse samples and tight delivery schedules, Elite recommends an "analytical + preparative" combination: the EClassical 3200 for method development and the EClassical 3150 for purification. The two systems are method-compatible and data-interoperable. The S3320 tray design supports continuous multi-batch operation, maximizing equipment utilization.
Used for purification of synthetic intermediates, removal of catalyst residues, and preparation of high-purity chemicals. High resolution and reproducibility ensure the purity and quantitative accuracy of reference standards. The 30 MPa working pressure and wide flow range accommodate various column specifications.
IV. Routine Maintenance and Care
After daily experiments, thoroughly flush the pump head with pure water. When using buffer salts, first transition-flush with a salt-free aqueous phase to prevent salt crystallization from wearing the plunger. Regularly inspect the plunger surface for scratches and replace if abnormal. If the check valve shows increased pressure fluctuations or reduced flow accuracy, disassemble and ultrasonically clean with methanol, or replace. Elite's modular design facilitates pump head maintenance, allowing users to replace wear parts themselves.
Preparative columns are costly, and proper care significantly extends their service life. Before use, confirm mobile phase compatibility with the packing. Avoid prolonged operation of reversed-phase columns with pure water or high aqueous phases. Samples must be filtered through 0.45 μm or 0.22 μm membranes. After experiments, remove the column from the system, flush with an appropriate storage solvent (typically methanol or acetonitrile for reversed-phase columns), and seal for storage. Elite SinoChrom preparative columns offer good method scale-up consistency, enabling seamless transition from analytical to preparative scale.
The core components of a UV detector are the flow cell and light source lamp. Watch for air bubbles in the flow cell, which increase baseline noise. If baseline drift or abnormal noise occurs, check the deuterium lamp lifespan (typically 1000–2000 hours) and replace promptly. If the flow cell is contaminated, flush with methanol-water at low flow rate. Elite detectors feature wavelength self-diagnostic functions for periodic automatic calibration.
Focus on the injection needle, metering pump, and switching valve. Regularly check for needle bending or blockage, and for aging or leaking needle seat seals. During continuous operation, periodically run the needle cleaning program to prevent cross-contamination. The rotor seal of the fraction collection valve is a wear part; replace promptly if leakage or sluggish switching occurs. The S3320 uses independent injection and collection tubing to reduce cross-contamination risk, and its modular structure facilitates quick replacement of wear parts.
Use HPLC-grade organic solvents and ultrapure water prepared fresh daily for the aqueous phase. Buffer salt solutions should not be stored for long periods to prevent microbial growth. Mobile phases must be degassed before use, and online degassers should be checked regularly. Clean solvent bottles periodically to avoid salt crystals flaking off and wearing pump components.
V. Summary
Selecting a fully automated preparative liquid chromatography system requires comprehensive consideration of purification scale, flow rate, pump performance, detector configuration, fraction collection automation, and expandability. Elite has built a complete product matrix from the 3140AP and EClassical 3500/3700 to the Elite IPC-50, covering microgram-scale analysis to ten-gram-scale preparation. Standardized maintenance—regular pump head flushing, proper column storage, timely light source replacement, automatic fraction collection flow path maintenance, and strict mobile phase management—is key to long-term stable operation. Choosing Elite means choosing a complete purification solution from hardware to software, and from method development to technical support.
