Detection of Trace-Level Herbicides in Drinking, Surface and Ground Water Using the Agilent 1200 Infinity Series Online SPE Solution

Importance of the Topic

Monitoring low-level herbicides and their metabolites in drinking, surface and ground waters is critical for environmental safety and regulatory compliance. Trace detection supports water quality assessment and helps protect public health and ecosystems.

Objectives and Study Overview

This work evaluates an automated online solid-phase extraction (SPE) coupled with high-performance liquid chromatography and triple quadrupole mass spectrometry to quantify 27 neutral herbicides and transformation products. The method meets German DIN 38407-36 guidelines and underwent interlaboratory validation across multiple water matrices.

Methodology and Instrumentation

An Agilent 1200 Infinity online SPE system employing dual PLRP-S trapping columns enabled direct enrichment of large sample volumes (up to 900 µL) with automated valve switching. Elution and separation used an Agilent ZORBAX Eclipse Plus C18 column and a binary gradient. Detection was performed on an Agilent 6460 triple quadrupole LC/MS with Jet Stream ESI in dynamic MRM mode. Performance optimization included source and collision energy tuning using MassHunter software.

Main Results and Discussion

Calibration curves for 23 analytes exhibited excellent linearity (R2 > 0.999) at 10–500 ng/L without weighting. Limits of quantitation below 25 ng/L were achieved for most compounds. Apparent recoveries ranged from 80% to 120% in tap, ground and surface waters; a few hydrophobic or highly polar analytes showed deviations up to 30%. Area precision was generally below 5% RSD and retention time reproducibility was < 0.1% RSD. Alternate use of trapping columns demonstrated consistent performance and high throughput.

Benefits and Practical Applications

The automated online SPE workflow reduces manual sample preparation time, solvent consumption and potential contamination. It supports routine monitoring laboratories by delivering robust trace-level quantification in diverse water types, including challenging matrices with particulate matter or high organic load.

Used Instrumentation

• Agilent 1200 Infinity Series Online SPE Solution with Flexible Cube and dual 2-position/10-port valve
• Agilent 1260 Infinity Quaternary Pump and Standard Autosampler (900 µL head)
• Agilent 1290 Infinity Thermostat and Flexible Cube
• Agilent ZORBAX Eclipse Plus C18 column with inline filter
• Agilent 6460 Triple Quadrupole LC/MS System with Jet Stream ESI

Future Trends and Applications

Further integration with high-resolution mass spectrometry could expand target lists and improve compound identification. Miniaturization of SPE media and faster chromatographic gradients promise enhanced throughput. Coupling with data analytics and real-time monitoring platforms may transform water quality surveillance.

Conclusion

The Agilent online SPE–LC–MS/MS approach reliably quantifies multiple herbicides and metabolites at low ng/L levels in varied water matrices. The method’s precision, sensitivity and automated workflow align with regulatory standards and support large-scale environmental monitoring.

References

1. DIN 38407-36: German Standard Methods for the Examination of Water, Wastewater and Sludge – Determination of Selected Neutral Herbicides by HPLC-MS/MS.
2. EU Council Directive 98/83/EC: Quality of Water Intended for Human Consumption.
3. Naegele E. et al. Agilent Application Note 5991-1738EN: Trace-Herbicide Quantitation by Online SPE and Triple Quadrupole MS.