Analysis of Dicamba and 2,4-D by the Triple Quad LCMS-8060

Importance of the topic

Accurate measurement of ultratrace herbicide actives like dicamba and 2,4-D within complex commercial formulations is essential for environmental safety, regulatory compliance, and quality assurance in agrochemical production.

Study objectives and overview

This application note evaluates the sensitivity, repeatability, and robustness of the Shimadzu LCMS-8060 triple quadrupole mass spectrometer for quantifying dicamba and 2,4-D in a 100× diluted glufosinate herbicide matrix. Key targets include determining limits of detection (LOD), limits of quantitation (LOQ), calibration performance, and long-term precision under challenging matrix conditions.

Methodology

The method employs a rapid LC–MS/MS approach with simple methanol‐water mobile phases. Samples of commercial herbicide diluted 100× were spiked with dicamba and 2,4-D. Calibration ranges spanned 0.1–10 ppb for dicamba and 0.01–1 ppb for 2,4-D. LOD samples were prepared at 0.01 ppb and 0.001 ppb, respectively. Multiple injections of standards and quality controls, including 134 mid-level QC injections over ~24 hours, assessed method ruggedness. MRM transitions and source parameters were optimized using flow injection analysis in LabSolutions Connect software.

Used Instrumentation

• Shimadzu LCMS-8060 triple quadrupole mass spectrometer
• Shimadzu Nexera UHPLC system
• LabSolutions Connect software for parameter optimization
• Optimized source settings: probe voltage, collision gas pressure, nebulizing gas, drying/heating gas flows, interface temperature, desolvation line and heating block temperatures

Key results and discussion

• LOD achieved: 0.01 ppb for dicamba (S/N ~3–4) and 0.0001 ppb for 2,4-D (S/N ~13).
• LOQ achieved: 0.1 ppb for dicamba (S/N >20) and 0.01 ppb for 2,4-D (S/N >90).
• Calibration curves linear over the target ranges with R² > 0.993 for dicamba and R² > 0.996 for 2,4-D, employing 1/C² weighting.
• Mid-level QC precision over 134 injections: %RSD = 1.87% for dicamba and 3.16% for 2,4-D, demonstrating excellent long-term stability.
• LOD replicate injections showed %RSD ≤ 10.5% for dicamba and ≤ 5.8% for 2,4-D, confirming reliable detection at trace levels.

The method maintained performance in the presence of high surfactant and other matrix interferences, thanks to the LCMS-8060’s robust ion source design and removable desolvation line for simplified maintenance without breaking vacuum.

Benefits and practical applications

This LC–MS/MS workflow offers rapid development, high sensitivity, and reproducibility for herbicide residue analysis in formulated products. It supports routine QA/QC in agrochemical manufacturing, environmental residue monitoring, and regulatory testing laboratories.

Future trends and potential applications

Emerging directions include expansion to multi-residue pesticide screening, integration of automated sample preparation and data processing, further miniaturization of MS sources, and deployment in high-throughput environmental and food safety laboratories.

Conclusion

The Shimadzu LCMS-8060 platform delivers ultralow detection limits, robust matrix tolerance, and consistent performance for dicamba and 2,4-D analysis in complex herbicide formulations, making it well suited for routine trace quantitation in research and quality control settings.