Analysis of trace amount of 17-β-Estradiol and its metabolites in aqueous samples using online-SPE and accurate MSn analysis

Importance of the Topic

Endocrine disrupting estrogens such as 17-β-estradiol and its conjugates are increasingly detected in water at trace levels and pose potential health risks due to reactivation of conjugated forms

Objectives and Study Overview

• Develop a qualitative analytical system for trace analysis of 17-β-estradiol and derivatives in aqueous matrices
• Combine online solid phase extraction with accurate multistage mass spectrometry

Methodology and Instrumentation

Sample preparation involved filtration through 0.45 µm membrane and injection of 5 mL into an online SPE unit. A preparative SPE column was used for enrichment followed by a C18 analytical column (Shimpack XR-ODS II 75×2 mm). Mobile phases were water with 10 mM ammonium acetate and methanol. Flow rates were 2 mL/min for loading and 0.25 mL/min for analysis at 40°C. An ESI ion trap time-of-flight mass spectrometer performed MS2 and MS3 with accurate mass measurement.

Used Instrumentation

• Nexera online SPE system
• LCMS-IT-TOF mass spectrometer
• SIL-10AP autosampler
• MAYI-ODS preparative SPE column
• Shimpack XR-ODS II analytical column

Main Results and Discussion

Chromatographic separation allowed detection of estradiol and four conjugates (E2-3G, E2-17G, E2-3S-17S, E2-3S-17G) at levels down to 2 ppt in river water. Accurate MS2 and MS3 spectra yielded mass errors below 3 mDa and signal to noise ratios between 10 and 38. These data confirmed structural assignments of each conjugate.

Benefits and Practical Applications

• Provides sensitive and selective monitoring of estrogenic compounds without deconjugation steps
• Supports environmental surveillance and water quality assessment
• Enables regulatory compliance for trace hormone pollutants

Future Trends and Opportunities

Extending this workflow to other endocrine disruptors and microbial metabolites is anticipated. Integration with high throughput platforms and further miniaturization could enhance field deployability and screening capacity.

Conclusion

This study demonstrates an efficient online SPE and accurate MSn approach for trace analysis of estradiol and metabolites in water, achieving reliable identification and quantitation at sub-ppt levels. The method offers a robust tool for environmental monitoring of hormone contaminants.

Reference

Tanigawa T, Ogura T, Hirano I, Iida J Analysis of trace amount of 17-β-estradiol and its metabolites in aqueous samples using online-SPE and accurate MSn analysis ASMS 2012 MP21-527