Automated Online SPE for LC/MS/MS Analysis of Trace Organic Contaminants in Water Using the Agilent 1290 Infinity Flexible Cube Module

Importance of the Topic

Monitoring trace organic contaminants (TOrCs) in water is critical due to widespread use of pharmaceuticals, personal care products, industrial chemicals, and pesticides that can persist in aquatic environments. Although individual compounds often occur at low concentrations, their long-term and mixture effects on ecosystems and human health remain uncertain.

Objectives and Study Overview

This study aimed to develop a single, fully automated online solid-phase extraction (SPE) coupled to liquid chromatography–tandem mass spectrometry (LC/MS/MS) method capable of detecting and quantifying 34 representative trace organic compounds at nanogram-per-liter levels in diverse water matrices within a 15-minute cycle using less than 2 mL of sample.

Used Instrumentation

• Agilent 1290 Infinity Flexible Cube LC module with dual SPE cartridges and 10-port valve
• Agilent 1200 Binary Pump and 1200 Autosampler with 900 µL metering device
• Agilent 6460 Triple Quadrupole LC/MS with simultaneous positive/negative electrospray ionization (ESI) and fast polarity switching
• Agilent Poroshell 120 EC C18 analytical column (50 × 2.1 mm, 2.7 µm)

Methodology and Process

A sample of 1.7 mL was loaded onto one SPE cartridge in the LOAD position while the other cartridge was conditioned. After loading, the valve switched to ELUTE and retained analytes were transferred to the analytical column using a step gradient. Simultaneously, the second cartridge was cleaned and re-equilibrated. Dynamic multiple reaction monitoring (MRM) transitions were optimized for each analyte, enabling rapid polarity switching and quantitation.

Main Results and Discussion

• Method detection limits (MDLs) for most analytes were below 5 ng/L, with four compounds slightly higher.
• Calibration was linear from MDL to 100 ng/L (R² > 0.99 for all targets).
• Intra- and inter-day precision showed relative standard deviations mostly below 10%.
• Analysis of environmental samples (surface water, groundwater, septic tank, and wastewater influent/effluent) confirmed method applicability for detecting and monitoring TOrCs and evaluating treatment efficiency.

Benefits and Practical Applications

• High throughput with a 15-minute cycle and minimal manual intervention
• Reduced sample volume (1.7 mL) and solvent consumption
• Enhanced reproducibility and accuracy through automated sample preparation
• Simultaneous detection in positive and negative ion modes in a single run

Future Trends and Applications

Expanding this approach to include additional emerging contaminants, integrating high-resolution mass spectrometry for non-target screening, and developing real-time online monitoring platforms could further improve water quality assessment. Green chemistry strategies may also reduce solvent usage and enhance sustainability.

Conclusion

The fully automated online SPE–LC/MS/MS method using the Agilent 1290 Infinity Flexible Cube and 6460 Triple Quadrupole provides a robust, rapid, and sensitive solution for the analysis of multiple trace organic contaminants in water, delivering significant gains in throughput, reproducibility, and resource efficiency.

References

1. Anumol T, Snyder S. Rapid analysis of trace organic compounds in water by automated online solid-phase extraction coupled to liquid chromatography–tandem mass spectrometry. Talanta. 2015;132:77-86.
2. Anumol T, et al. Ultra high performance liquid chromatography tandem mass spectrometry for rapid analysis of trace organic contaminants in water. Chem Cent J. 2013;7:104.