Smarter automated SPE for antibiotic monitoring

Pharmaceuticals in the environment

Pharmaceuticals are indispensable in modern healthcare, consumed daily in vast quantities for both prophylactic and therapeutic purposes. After use, many active pharmaceutical ingredients (APIs) are excreted—sometimes metabolized, often unchanged—into wastewater systems. Conventional wastewater treatment plants (WWTPs), however, are not optimized for the complete removal of such micropollutants, resulting in their continued discharge into surface waters.

Among these residues, antibiotics have become a major focus. They transformed medicine by making once-fatal bacterial infections treatable, but their widespread occurrence in aquatic systems is of ecotoxicological concern. Even at low concentrations, antibiotics can alter microbial communities and drive the selection of resistant bacteria, which may transfer resistance genes to other species. Nationwide surveys have confirmed the presence of human and veterinary drugs in the majority of surface and groundwater downstream of urban areas and livestock production sites, highlighting wastewater effluents and agricultural runoff as important sources.

In agriculture, residues excreted in manure and applied to fields can leach into groundwater and surface waters; while in human healthcare, excreted or improperly disposed drugs enter sewage networks. Because WWTPs are not designed to completely remove these compounds, effluents often act as points of continuous release. As a result, WWTPs are regarded as hotspots for antimicrobial resistance (AMR), where diverse bacterial consortia are exposed to trace levels of antibiotics under conditions that favor the emergence and proliferation of resistance genes.

Regulation and monitoring

In recognition of these risks, the European Union (EU) Watch List of Pharmaceuticals in Water, established under the Water Framework Directive, mandates member states to monitor selected pharmaceutical contaminants, including several antibiotics, in both surface and groundwater. This initiative is intended to generate high-quality occurrence data to underpin evidence-based policy decisions. As the Watch List continues to evolve, laboratories face increasing pressure to deliver reproducible, high-throughput analyses of pharmaceuticals at ultra-trace levels.

Table 1. Antibiotics which have appeared on the EU Watch List. 

Amoxicillin (β-lactam)	Ciprofloxacin (fluoroquinolone)	Erythromycin (macrolide)	Sulfamethoxazole (sulfonamide)	Oxytetracycline (tetracycline)

Analysis

Currently, liquid chromatography coupled with tandem mass spectrometry (LC–MS²) represents the gold standard for determinations of pharmaceuticals in water matrices. However, the typically low environmental concentrations warrant a preconcentration step prior to analysis. Solid phase extraction (SPE) remains the most widely employed technique for this purpose, with Biotage^® consumables such as:

• EVOLUTE^® EXPRESS ABN – broad-spectrum sorbent for acidic, basic, and neutral analytes
• EVOLUTE^® EXPRESS WCX – ideal for extraction of strongly basic compounds
  • ISOLUTE^® C18 – for neutral to moderately polar pharmaceuticals
  • ISOLUTE^® ENV+ – for polar analytes that are not retained by C18 or C8 sorbents
  • EVOLUTE^® EXPRESS WAX – ideal for extraction of strongly acidic analytes
  •  

• By exploiting different sorbents, you can build workflows that are both flexible and compound specific.

  The limitations of traditional SPE

  Traditional SPE workflows, however, are encumbered by several limitations:

  • - Sample volumes typically in the range of 0.1–1.0 L
  • - Multiple manual handling steps
  • - Time-consuming extractions
  •  

  These factors introduce variability, increase the likelihood of procedural error, and impose significant throughput constraints—particularly under the demands of regulatory monitoring regimes.

  Automated SPE: Biotage^® PrepXpert-8

To address these challenges, we have developed the Biotage^® PrepXpert-8, an automated SPE platform capable of processing up to eight samples in parallel.

Figure 1. Biotage® PrepXpert-8 fully automated sample preparation system

The system combines dual method compatibility with an intuitive user interface, while offering robust data management that generates detailed run reports and integrates seamlessly with laboratory information management systems (LIMS). Its key features also include:

• - Syringe-barrel positive pressure control for uniform pressure across multiple cartridges
• - Simplified sample handling with direct loading, bottle rinsing and support for up to two stacked columns
• - Reagent and waste level monitoring
• - Consistent flow rates, precise solvent handling and tightly controlled extraction conditions

By eliminating repetitive manual interventions, the system not only minimizes the risk of error but also frees up time to focus on data analysis rather than sample preparation logistics.

From sample prep to results: A smarter workflow

Here’s how it all fits together:

Looking ahead

For laboratories engaged in monitoring pharmaceuticals under the EU Watch List, or in broader environmental surveillance, Biotage^® PrepXpert-8 provides a robust and scalable solution. Its automation facilitates both the generation of high-quality, regulatory-compliant data and the throughput necessary to meet the growing analytical demands associated with pharmaceutical contaminants in water and beyond.

We’ll be sharing more details on this workflow in an upcoming application note, where we’ll delve deeper into the methodology and results. Until then, you can learn more about the processing system behind it all — the Biotage^® PrepXpert-8 — and see how it helps laboratories tackle today’s environmental-analysis challenges. Its automation reduces hands-on time, freeing you to focus on higher-value tasks such as data analysis and method development.

Related products:

Biotage® PrepXpert-8

EVOLUTE® SPE Columns 

TurboVap® LV