Qualitative and Quantitative Analysis of Contaminants of Emerging Concern in Biosolids Using a Dilute and Shoot UHPLC-Orbitrap MS Method

Importance of the Topic

Biosolids generated by wastewater treatment contain trace levels of pharmaceuticals, personal care products and endocrine-disrupting chemicals that can accumulate in soils and threaten ecosystems and human health. Rapid and reliable analytical methods are essential for monitoring these contaminants of emerging concern (CECs) in treated sludge and amended soils.

Study Objectives and Overview

This study presents a dilute-and-shoot workflow using full-scan high-resolution accurate-mass (HRAM) UHPLC-Orbitrap MS to quantify 49 targeted CECs in biosolids and to screen for 381 non-target compounds. The aim was to evaluate method performance, identify priority analytes and demonstrate simultaneous targeted and non-targeted analysis in complex matrices.

Methodology and Instrumentation

Sample Preparation and Extraction:

• Biosolids and biosolids-amended soils were dried, sieved (200 μm), homogenized and stored frozen.
• 5 g aliquots extracted with two 20 mL washes of acetonitrile/0.1% acetic acid (70:30, v/v) plus 1 mM EDTA under ultrasonic agitation.
• Combined extracts diluted to 50 mL, centrifuged, evaporated and reconstituted in 100 μL internal standard solution.

Chromatography and Mass Spectrometry:

• Thermo Scientific Dionex UltiMate 3000 UHPLC with Betasil and Hypersil GOLD columns.
• Gradient elution with ammonium formate/acetate buffers in methanol or acetonitrile.
• Thermo Scientific Exactive Plus Orbitrap MS with HESI II source, full-scan at 140 000 resolution.
• Quantitative processing with TraceFinder; non-targeted screening via predicted adducts and isotopic patterns, followed by SIEVE/ChemSpider search.

Main Results and Discussion

Extraction optimization showed equivalent recoveries for acetonitrile- and methanol-based solvents. Method detection limits ranged from 6 to 572 ng/g, recoveries 54–141% and RSDs below 20%. Targeted analysis in six biosolids revealed high ppb levels of bisphenol A, caffeine, carbamazepine, triclocarban and triclosan. Non-targeted screening identified surfactants, artificial sweeteners, musks, flame retardants and known transformation by-products.

Benefits and Practical Applications

This dilute-and-shoot HRAM approach enables high-throughput monitoring of both known and emerging pollutants without extensive cleanup. It supports regulatory compliance, risk assessment and environmental fate studies by providing comprehensive chemical profiles in biosolids and soils.

Future Trends and Potential Applications

Advances may include expanded non-target databases, machine-learning assisted identification, coupling with ion mobility separation, in situ field-deployable HRMS and integration into long-term monitoring networks to assess treatment efficiency and ecological impact.

Conclusion

The described UHPLC-Orbitrap method delivers robust quantitative and qualitative data on a broad spectrum of CECs in biosolids. Its simplicity, sensitivity and versatility make it a valuable tool for environmental laboratories and regulatory agencies.

References

• Ternes TA, Joss A, Eds. Human Pharmaceuticals, Hormones and Fragrances: The Challenge of Micropollutants. Urban Water Management, IWA, 2006, p 443.
• Kortenkamp A. Environmental Health Perspectives, 2007, 1–42.