AN AUTOMATED SYSTEM FOR THE ROUTINE CLEAN-UP OF ENVIRONMENTAL SAMPLES PRIOR TO INSTRUMENT ANALYSIS

Significance of the Topic

Effective removal of interferences such as lipids, oils and sulphur from environmental extracts is critical to achieve reliable, high-sensitivity instrumental analysis, protect chromatography columns and ensure compliance with regulatory methods.

Study Objectives and Overview

The aim of this work was to develop and validate an automated clean-up workflow for diverse environmental matrices based on US EPA procedures 3640 and 3640A, integrating gel permeation chromatography (GPC) and solid-phase extraction (SPE) prior to GC/MS detection. A preconfigured system combining Agilent 1260 Infinity HPLC modules and EnviroPrep clean-up columns was evaluated using mussel tissue extracts as a model sample.

Methodology

Samples (2 g homogenized mussel tissue) were extracted by accelerated solvent extraction (ASE) with dichloromethane/acetone (50:50). Extracts were concentrated and injected onto a GPC clean-up system employing Agilent EnviroPrep columns. The target fraction (17.7–27.2 min) was collected, solvent-exchanged to n-hexane and evaporated. A polishing step using SPE (silica gel for PAHs, florisil for OCPs, acid clean-up and alumina SPE for PCBs) removed residual interferences prior to final GC/MS analysis.

Used Instrumentation

• Agilent 1260 Infinity Quaternary Pump (G1311B)
• Agilent 1260 Infinity Autosampler (G1329B) with extended range and multi-draw
• Agilent 1260 Infinity Variable Wavelength UV Detector (G1314B)
• Agilent 1260 Infinity Fraction Collector (G1364C) with thermostat (G1330B)
• Agilent EnviroPrep GPC column (300×25 mm) and PLgel Prep Guard (25×25 mm)

Main Results and Discussion

System calibration with a Restek EPA test mixture allowed definition of fractionation windows that separate target analytes from macromolecular contaminants and sulphur. GC/MS analysis of cleaned mussel extracts demonstrated clear removal of lipids and sulphur, improved chromatographic performance and reliable detection of OCPs, PAHs and PCBs at trace levels.

Benefits and Practical Applications

• Automated, reproducible clean-up increases laboratory throughput and consistency
• Effective removal of matrix interferences extends column lifetime and data quality
• Applicable to a broad range of environmental and food matrices following standardized EPA protocols

Future Trends and Opportunities

Further integration with mass spectrometry and high-resolution detection, miniaturization of clean-up formats, adoption of greener solvents and advanced data analysis workflows will enhance sensitivity, reduce solvent consumption and enable high-throughput environmental monitoring.

Conclusion

The preconfigured Agilent GPC Sample Clean-Up system provides a robust, EPA-compliant solution for routine removal of lipids and sulphur from environmental samples, ensuring improved accuracy and reproducibility in GC/MS analysis of trace organic pollutants.

References

• Clean Seas Environment Monitoring Programme (CSEMP), Marine Assessment and Review Group, UK.
• EPA Method 3640A – Gel Permeation Clean-Up.