What are the most common automated sample preparation techniques?

The most common automated sample preparation techniques are solid phase extraction (SPE), pressurized liquid extraction (PLE), Soxhlet-based solvent extraction, and automated cleanup or purification systems. These methods cover the two core stages of sample preparation: extraction, which isolates target analytes from a matrix, and purification, which removes interfering compounds before instrumental analysis. The sections below address the most frequently asked questions about how these techniques work, where they apply, and what to consider when selecting a system.

Which sample preparation techniques are most widely automated?

The techniques most commonly automated in modern laboratories are solid phase extraction (SPE), pressurized liquid extraction (PLE), Soxhlet solvent extraction, and column-based cleanup or purification. Automation has been applied most successfully to workflows that are repetitive, solvent-intensive, or require precise timing, as these are exactly the conditions where manual handling introduces variability and risk.

SPE is the most broadly adopted of these, used across environmental, food safety, and clinical laboratories for isolating contaminants from liquid and solid matrices. Automated SPE platforms can process dozens of samples in parallel, dramatically reducing analyst time per sample while maintaining reproducibility.

Soxhlet-based extraction, traditionally a slow and solvent-heavy process, has been modernized through systems like the Randall-principle approach, which performs extraction directly in boiling solvent followed by a hot Soxhlet or Twisselmann step. This reduces solvent use significantly while maintaining recovery rates comparable to classical Soxhlet methods.

Automated purification systems represent a third category, particularly relevant for persistent organic pollutants (POPs) such as dioxins, PCBs, and PBDEs. These systems automate multi-column cleanup sequences that would otherwise require hours of careful manual work, and they are especially valuable in high-throughput regulatory monitoring laboratories.

How does automated solid phase extraction work?

Automated solid phase extraction works by passing a liquid sample through a sorbent-packed cartridge or disk that selectively retains target analytes while allowing matrix interferences to pass through. The retained compounds are then eluted with a small volume of solvent, producing a concentrated, purified extract ready for instrumental analysis. Automation controls flow rates, solvent volumes, and timing across multiple channels simultaneously.

In a manual SPE workflow, an analyst must condition the cartridge, load the sample, wash away interferences, and elute the analytes, repeating this sequence for every individual sample. Automated systems replicate this sequence across multiple cartridges in parallel, guided by programmed methods that ensure consistent pressure, solvent delivery, and fraction collection.

Modern automated SPE platforms support a range of cartridge formats, from 1 mL to 12 mL, and can handle sample volumes from 10 mL up to 1,000 mL depending on the application. Large-volume extraction configurations, such as those using 47 mm or 90 mm disk formats, are particularly suited to water samples where analyte concentrations are very low and large volumes must be processed to achieve the required detection limits.

Fraction collection is another area where automation adds value. Systems can collect multiple fractions per sample, separating compound classes with different polarities into distinct vials for separate analysis, something that is difficult to execute consistently by hand across a large sample batch.

What is the difference between automated SPE and pressurized liquid extraction?

The key difference between automated SPE and pressurized liquid extraction (PLE) is where each technique operates in the sample preparation workflow. SPE is primarily a purification and concentration technique applied to liquid extracts, while PLE is an extraction technique that uses elevated temperature and pressure to pull analytes out of solid or semi-solid matrices using organic solvents.

PLE, also known as accelerated solvent extraction (ASE) or pressurized fluid extraction, works by heating a solvent above its atmospheric boiling point under pressure, which increases its solvating power and speeds up analyte transfer from the matrix into the liquid phase. This makes it well suited for extracting contaminants from complex solid matrices such as soil, sediment, food, and biological tissue.

SPE, by contrast, starts with a liquid sample or liquid extract and selectively retains target compounds on a sorbent material. The two techniques are frequently used in sequence: PLE first extracts analytes from a solid matrix into solution, and SPE then cleans up and concentrates that extract before analysis.

Soxhlet-based systems occupy a related but distinct position. They also extract from solid matrices, but rely on repeated cycles of condensing solvent washing through the sample rather than pressurized conditions. Automated Randall-principle systems improve on classical Soxhlet by reducing extraction time and solvent consumption while maintaining comparable recovery performance, making them a practical middle ground for laboratories that need solid-matrix extraction without investing in full PLE instrumentation.

Which contaminants are best suited to automated sample preparation?

Automated sample preparation is best suited to contaminants that require multi-step cleanup, are present at trace or ultra-trace levels, or are regulated under strict analytical standards that demand high reproducibility. Persistent organic pollutants (POPs) such as dioxins, PCBs, and PBDEs, as well as PFAS, pesticides, PAHs, hormones, and SVOCs, are the compound classes most commonly analyzed using automated preparation workflows.

Dioxins and PCBs are particularly demanding to prepare manually. Their analysis requires extensive lipid removal and multi-column purification before GC-MS or HRMS measurement, and any inconsistency in the cleanup sequence affects both recovery and selectivity. Automated purification systems handle these sequences with high reproducibility, reducing the risk of analyst-to-analyst variation in results.

PFAS analysis presents a different challenge. PFAS compounds are highly surface-active and prone to contamination from laboratory materials, particularly those containing fluoropolymers such as Teflon. Automated SPE systems with fully inert, Teflon-free flow paths are specifically designed to address this, ensuring that background contamination does not compromise results at the low concentration levels regulators require.

Pesticides, hormones, and PAHs are also well served by automated SPE, particularly in food and water monitoring programs where large numbers of samples must be processed to consistent quality standards. Automation enables laboratories to meet these throughput demands without proportionally increasing analyst headcount or error rates.

How does automation reduce solvent use in sample preparation?

Automation reduces solvent use in sample preparation by delivering precise, programmed volumes of solvent at each step, eliminating the over-application that commonly occurs in manual workflows. Automated systems also enable extraction techniques that are inherently more solvent-efficient than classical methods, such as Randall-principle extraction and small-cartridge SPE, bringing total solvent consumption per sample well below what manual Soxhlet or liquid-liquid extraction typically requires.

In classical Soxhlet extraction, solvent consumption can reach several hundred milliliters per sample. Automated extraction systems based on the Randall principle reduce this to less than 100 mL per sample, achieving comparable recoveries in a fraction of the time. This matters both for laboratory operating costs and for analyst safety, as lower solvent volumes mean reduced vapor exposure and less hazardous waste to dispose of.

Automated purification platforms for POPs analysis have similarly reduced solvent requirements. Systems designed for dioxin and PCB cleanup operate without dichloromethane, historically one of the most widely used but toxicologically problematic solvents in this application area. By replacing it with less hazardous alternatives and minimizing total volume through precise delivery, these platforms contribute meaningfully to greener laboratory practice.

The environmental and regulatory case for solvent reduction is growing stronger each year. In 2026, laboratories face increasing pressure to document and reduce their chemical waste footprint, and automated systems that can demonstrate measurably lower solvent consumption per sample provide a tangible compliance and sustainability advantage.

What should laboratories consider when choosing an automated preparation system?

When choosing an automated sample preparation system, laboratories should evaluate sample throughput requirements, the range of matrices and analytes they analyze, solvent compatibility, regulatory method alignment, and the level of integration needed with downstream analytical instruments. No single system suits every application, so matching the platform to the laboratory’s specific analytical scope is the most important decision factor.

Throughput and batch size: Consider how many samples need to be processed per day or per run. Systems vary widely, from platforms that process 6 to 8 samples per run to high-capacity configurations handling 80 or more samples in a single sequence.
Matrix diversity: Laboratories analyzing both solid and liquid matrices may need separate extraction and purification platforms, or a system that can accommodate both with minimal reconfiguration.
Cartridge and volume flexibility: Confirm that the system supports the cartridge sizes and sample volumes relevant to your methods, particularly if you work across applications with very different volume requirements.
Solvent and material compatibility: For PFAS analysis, inert flow paths free of Teflon and other fluoropolymers are essential. For any application, verify that wetted components are compatible with the solvents your methods require.
Regulatory method compliance: Check whether the system has been validated or applied in the context of the methods you follow, such as EPA 1613B, EPA 1668A, or relevant CEN standards for food and environmental monitoring.
Integration and software control: Assess how the system connects with your laboratory information management system (LIMS) and whether its software supports audit trails, method locking, and the documentation requirements of accredited laboratories.
Vendor support and training: Automated systems require commissioning, method setup, and ongoing maintenance. Evaluate whether the supplier provides application support, training, and local service capability.

Cost of ownership is another dimension that is often underweighted at the point of purchase. Solvent savings, reduced analyst time, and lower error rates all contribute to the return on investment, and these should be modeled against the capital cost of the system when comparing options.

How DSP-Systems help with automated sample preparation

DSP-Systems supplies and supports a curated range of automated sample preparation systems specifically selected for laboratories analyzing environmental contaminants, food safety parameters, and persistent organic pollutants. Their offering covers the full preparation workflow, from extraction through purification and concentration, with systems validated against regulatory methods used in Europe and North America.

GO-EHT purification systems for dioxins, PCBs, PBDEs, and PCNs, using less than 100 mL of solvent per sample and eliminating dichloromethane from the workflow
SPE2000 for high-throughput SPE of PFAS, pesticides, hormones, SVOCs, and PAHs, processing up to 80 samples per run across cartridge sizes from 1 mL to 12 mL
AutoEmpore for large-volume water sample extraction with automatic online filtration, available in multi-channel configurations for parallel or series operation
SER-158 for automated Randall-principle extraction of solid and semi-solid samples, compatible with GO-EHT cleanup systems for an integrated end-to-end workflow
MultiVap and CentriVap concentration systems for solvent evaporation and sample concentration prior to GC or LC injection
Pre-installation programming, SPE application testing, and configuration in line with EPA and CEN standards

Whether you are setting up a new laboratory, scaling an existing workflow, or looking to reduce solvent use and improve reproducibility, DSP-Systems can help you identify the right platform for your specific analytical needs. Contact DSP-Systems to discuss your requirements with a specialist.

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