Analysis of golf course pesticides using LC-MS

Importance of the Topic

Maintaining green turf on golf courses requires the application of various pesticides. Despite lower usage compared to agriculture, golf courses are often adjacent to water bodies, raising concerns about pesticide runoff and regulatory limits for river and drinking water quality. Sensitive and selective analytical approaches are essential to ensure environmental safety and compliance.

Goals and Study Overview

This study demonstrates an example LC-MS method for simultaneous analysis of common golf course pesticides—acephate, asulam, thiram, triclopyr, bensulide, MCPP, and pencycuron. The objectives were to optimize chromatographic separation, evaluate detection in full-scan and selected ion monitoring (SIM) modes, and establish calibration curves for quantitation at low concentrations.

Methodology and Instrumentation

The method employs reversed-phase liquid chromatography on a VP-ODS semi-micro column (2.0 mm I.D. × 150 mm) with a water/10 mM ammonium acetate (pH 4)–acetonitrile gradient. A maximum injection volume of 5 µL enhances sensitivity. Electrospray ionization (ESI) was used in both positive and negative modes, scanning m/z 50–600 at 1.5 s/scan and monitoring specific ions for each compound.

• Column temperature: 40 °C
• Flow rate: 0.2 mL/min
• ESI voltages: +4.5 kV (positive), –3.0 kV (negative)
• Probe/Block heater temperature: 200 °C
• Nebulizing gas flow: 4.5 L/min; CDL voltage: –15 V (positive), +15 V (negative)

Main Results and Discussion

Full-scan chromatograms achieved baseline separation of all target pesticides within a 15-minute gradient. Mass spectra confirmed molecular ions at m/z 228.9 for asulam, 240.8 for thiram, and 326.9 for pencycuron, along with characteristic fragment peaks. SIM analysis at 10–50 ppb produced well-defined peaks with precise retention times.
Calibration curves based on five replicate injections exhibited excellent linearity (r2 ≥ 0.9998) over the tested concentration ranges. Method precision was demonstrated with relative standard deviations below 1% across all analytes.

Benefits and Practical Applications

• High sensitivity and selectivity enabling multi-residue analysis in a single run
• Low detection limits compatible with environmental regulatory standards
• Rapid analysis time (<15 min) supporting high sample throughput

Future Trends and Opportunities

Emerging high-resolution mass spectrometers and ambient ionization sources promise lower detection limits and streamlined sample preparation. Ultra-high-pressure LC and microflow systems may further reduce solvent use and analysis times. Automated sample handling and data processing will enhance routine environmental monitoring.

Conclusion

The described LC-MS approach offers a robust, sensitive, and reproducible solution for monitoring trace pesticide residues on golf courses. Its strong linearity, precision, and rapid run time make it well suited for environmental compliance and protection of water resources.

References

No external literature citations were provided in the source document.