Automation in preparative chromatography – discover the device best suited for your application

Significance of the topic

Preparative chromatography is integral to pharmaceutical, chemical and food industries for obtaining compounds at desired purity and yield. Automating sample injection and fraction collection streamlines workflows, minimizes human error and maximizes throughput. As demand for high-capacity and reproducible purifications grows, selecting the appropriate automation device becomes critical for efficient laboratory and production operations.

Study Objectives and Overview

This article compares two automation strategies offered by KNAUER: the AS 6.1L preparative autosampler paired with standalone fraction collectors, and the LH 2.1 liquid handler combining injection and fractionation. The goal is to guide users in choosing the optimal configuration based on sample volume, throughput requirements and application scope.

Methodology and Instrumentation

A side-by-side comparison of injection principles, volume ranges, throughput metrics and software compatibility was conducted. Key performance indicators include injection accuracy, sample loss, maximum number of injections, fractionation capacity and system flexibility. Instruments were evaluated under typical preparative conditions using pulled-loop injection schemes and detector-triggered fraction collection.

Instrumentation

• Preparative Autosampler AS 6.1L: Partial loop fill injection up to 10 mL, 60 µL fixed flush volume, biocompatible flow paths, sample cooling and integration into AZURA system tower.
• Liquid Handler LH 2.1: Partial and sandwich injection up to 60 mL, configurable racks for samples and fractions, combined autosampler and fraction collector, high throughput capacity.

Main Results and Discussion

The AS 6.1L excels in small-scale and semi-preparative runs (milligram range), offering low carry-over, ease of use and minimal footprint. Its partial loop mode ensures accurate volume delivery with minimal loss. In contrast, the LH 2.1 handles larger volumes (up to several grams of product), supports sandwich injections to eliminate dead-volume loss and unifies injection and fractionation in one platform. Fraction collector comparisons highlight FC 6.1 for low-volume tasks, LABOCOL Vario 4000 for intermediate capacity, and LH 2.1 for maximal throughput and flexible rack layouts.

Benefits and Practical Applications

• Improved reproducibility and reduced manual errors.
• Continuous operation with high sample throughput.
• Flexible scaling from analytical-to preparative applications.
• Compatibility with multiple chromatographic software suites.

Future Trends and Potential Uses

Emerging developments include tighter integration with robotic workstations, advanced online detectors, machine-learning driven method optimization and eco-friendly solvent management. Expanded modular designs will facilitate seamless scale-up and automated downstream processing.

Conclusion

For small-scale purifications, the AS 6.1L combined with FC 6.1 or LABOCOL Vario 4000 offers cost-effective automation. For high-throughput or gram-scale applications, the LH 2.1 liquid handler provides unmatched flexibility by merging injection and fraction collection. Instrument selection should be guided by sample volume, throughput targets and desired workflow integration.