Oasis® Sample Extraction Products for Agrochemical and Environmental Analysis

Significance of the topic

Solid-phase extraction using polymeric sorbents is essential in environmental, agrochemical and food analysis for efficient cleanup, concentration and reliable quantitation of trace organic compounds.

Objectives and overview of the study/article

This application note evaluates Waters Oasis HLB, MCX and MAX sample extraction cartridges for the determination of a broad range of analytes in aqueous, soil and food matrices. It compares retention, capacity, recoveries, breakthrough volumes and processing times with traditional C18 silica sorbents.

Methodology

The general SPE workflow consists of conditioning (methanol and water or mixed solvents), sample loading (up to 1000 mL), washing to remove interferences and elution with appropriate solvents (MeOH, MTBE mixtures, acidic or basic modifiers). Cartridges range from 1 cc/30 mg to 35 cc/6 g, 30–60 µm particle size. Sample extracts are evaporated and reconstituted prior to LC, GC or LC/MS analysis.

Used Instrumentation

• HPLC with UV and PDA detection on Waters Symmetry and XTerra C18 columns
• GC with FID or NPD detectors
• LC/MS with Waters Alliance Separations Module and Micromass ZMD™ in SIR mode

Main results and discussion

Oasis HLB exhibits higher retention factors and capacity than C18 silica for polar analytes such as salicylic acid, theobromine and catechol. Recoveries of phenols and acidic herbicides in drinking and well water ranged from 80–126% with RSDs ≤13%. A 60 mg HLB cartridge reduced processing time to 15 minutes, elution volume to 1 mL and achieved 90% recovery for sulfonylurea herbicides (LOQ 50 ng/L). Endocrine disruptors and polar metabolites were recovered at 80–120% (RSD ≤17%). MAX cartridges enabled quantitation of naptalam, 1-naphthylamine and clopyralid/triclopyr in the low µg/L range with consistent MS detection. MCX sorbents delivered 75–107% recovery for atrazine metabolites and 82–96% for basic fungicides. In natural products, HLB and MAX phases provided >80% recovery for goldenseal alkaloids, echinacea phenolics and ginkgo flavonoids from complex matrices.

Benefits and practical applications of the method

• High analyte recovery and reproducibility across a wide polarity range
• Reduced solvent and sample volumes, shorter processing times
• Compatibility with LC/UV, LC/MS and GC methods
• Robust performance in environmental, agrochemical and natural product analysis
• Patented hydrophilic–lipophilic balanced polymer offers enhanced cleanup and capacity

Future trends and potential applications

Advances may include automation and on-line SPE integration, miniaturized formats for ultra-trace analysis, development of green solvents, coupling with high-resolution mass spectrometry and tailored sorbent chemistries for emerging contaminants in environmental monitoring, food safety and metabolomics.

Conclusion

Waters Oasis HLB, MCX and MAX extraction cartridges deliver versatile, high-performance SPE solutions that outperform traditional silica phases in agrochemical, environmental and natural product analyses, enabling streamlined workflows and reliable quantitation of diverse organic compounds.

Reference

• Young MS. Waters Column VI, Issue 5. 1997.
• US Patent 5,882,521 (1996); 5,976,376 (1998); 6,106,721 (1999); 6,254,780 (2001); 6,322,695 (2001).