Rapid Separation of Eighteen Herbicides Using Advanced UHPLC and Sub-2 μm Solid Core Column Technologies

Importance of the Topic

Monitoring herbicide residues in environmental and food matrices is critical for regulatory compliance and public health. High-throughput, high-resolution chromatographic methods support rapid screening of multiple analytes at trace levels. Innovations in UHPLC and solid core column technology enable faster separations with improved sensitivity and resolution, meeting the growing demand in environmental analysis and quality control.

Objectives and Study Overview

The study compares the performance of the Thermo Scientific Accucore Vanquish C18 1.5 µm column and Vanquish UHPLC system against other sub-2 µm solid core and 2.6 µm core columns. Eighteen common herbicides are evaluated under identical gradient conditions to assess separation speed, peak capacity, resolution, sensitivity, and throughput.

Methodology

Sample Preparation:
A certified pesticide mix containing 18 herbicides at 10 µg/mL in acetonitrile was diluted 1:1 with water to yield a 5 µg/mL working solution.

Chromatographic Conditions:
Mobile phases: A = water; B = acetonitrile
Column temperature: 43 °C; injection volume: 0.5 µL; detection at UV 230 nm (0.1 s rise, 50 Hz, 8 nm slit)
Gradient on 1.5 µm column (0.65 mL/min): 0–4 min (80→60 % A), 4–7 min (60→20 % A), 7–7.5 min (20→80 % A), 7.5–12 min (80 % A)
Gradient on 2.6 µm column (0.38 mL/min): similar profile extended to 20.8 min.

Instrumentation

• Vanquish UHPLC system: Binary Pump H, Split Sampler HT, Column Compartment H, Diode Array Detector HL
• Accucore Vanquish C18, 1.5 µm, 100×2.1 mm column
• Virtuoso 9 mm vial kit and Viper fingertight fittings
• Chromeleon 7.2 Chromatography Data System

Main Results and Discussion

• Baseline separation of 16 out of 18 herbicides achieved in under 6 minutes on all sub-2 µm columns.
• The 1.5 µm column delivered average peak widths 21 % and 60 % lower than two competitor sub-2 µm columns, boosting peak capacity by 17 % and 37 %, respectively.
• Average resolution improved by 6 % and 31 % versus competitor (i) and (ii); peak heights rose by 11 % and 23 %, while retention times decreased by 3 % and 5 %.
• Scaling from a 2.6 µm to the 1.5 µm column reduced analysis time by 40 %, narrowed peak widths by 56 %, raised peak heights by 17 %, enhanced peak capacity by 31 %, and improved resolution by 24 %.

Benefits and Practical Applications

• High-throughput analysis of multiple herbicides in under 6 minutes increases laboratory productivity.
• Enhanced chromatographic efficiency supports trace-level detection in environmental and food safety testing.
• Robust core-shell particle design reduces secondary interactions, improving method ruggedness and reproducibility.
• Compatibility with high-pressure UHPLC systems enables method scale-up and automation.

Future Trends and Applications

Advances in sub-2 µm core-shell materials and high-pressure UHPLC are likely to extend rapid screening capabilities to other pesticide classes, pharmaceuticals, and complex biological matrices. Integration with mass spectrometry, microfluidic sample handling, and data-driven method optimization will further enhance sensitivity, selectivity, and throughput in routine and research laboratories.

Conclusion

The Accucore Vanquish C18 1.5 µm column paired with the Vanquish UHPLC system delivers rapid, high-resolution separation of 18 herbicides in under 6 minutes. Compared to both sub-2 µm and 2.6 µm competitor columns, it offers superior peak capacity, resolution, sensitivity, and throughput, making it an ideal choice for environmental monitoring and quality control applications.

References

• Kristina Kirkham, Luisa Pereira, Derek Hillbeck, Rapid Separation of Eighteen Herbicides Using Advanced UHPLC and Sub-2 µm Solid Core Column Technologies, Application Note 21001, Thermo Fisher Scientific, 2014.