UHPLC Analysis of a Pesticide Formulation Using the ACQUITY Arc System with PDA, Mass Detection, and Empower 3 Software

Significance of the Topic

The analysis of pesticide formulations is critical for ensuring product consistency, efficacy, and regulatory compliance in agricultural chemistry. Combining high-resolution chromatographic separations with complementary detection techniques enhances confidence in impurity profiling and structural characterization, supporting quality control and product registration efforts.

Objectives and Study Overview

This study aimed to demonstrate a single-injection workflow for profiling a commercial pesticide formulation containing two active ingredients (an insecticide AI 1 and the triazole fungicide tebuconazole AI 2). The approach integrates dual-flow path UHPLC and HPLC emulation with photodiode array and mass detection, managed by Empower 3 software, to identify, quantify, and flag impurities above predefined thresholds.

Methodology

Sample preparation involved dissolving 1 g of formulation in 9 mL of 50:50 acetonitrile/water, sonicating for 20 minutes, and syringe filtering through a 0.2 µm PVDF filter. UHPLC separations were performed on a CORTECS C18+ column (3.0×100 mm, 2.7 µm) using a gradient from 20% to 90% acetonitrile with 0.1% formic acid in water at 0.8 mL/min and 50 °C. PDA detection scanned 210–400 nm with peak monitoring at 220 nm. Mass detection employed an ACQUITY QDa in ESI+ mode (capillary voltage 0.8 kV, cone 10 V) scanning m/z 100–1000 at 5 Hz.

Instrumentation

• ACQUITY Arc System with dual-flow path technology
• 2998 Photodiode Array Detector
• ACQUITY QDa Detector
• CORTECS C18+ Column, 3.0×100 mm, 2.7 µm
• Empower 3 Chromatography Data Software

Main Results and Discussion

The UHPLC-PDA chromatogram resolved AI 1 at 1.50 min (29.1% area) and tebuconazole at 6.49 min (69.6% area). Two unknown impurities exceeded the 0.1% reporting threshold: Unknown 1 at 2.65 min (0.55%, m/z 281) and Unknown 2 at 4.88 min (0.77%, m/z 308). Mass analysis in Empower 3 correlated UV peaks with total ion chromatograms and extracted ion chromatograms, revealing that Unknown 2 shares the same m/z and isotopic chlorine pattern as tebuconazole, suggesting an isomeric relationship. Unknown 1 displayed a similar UV profile and chlorinated isotopic signature, indicating a related triazole impurity.

Benefits and Practical Applications

• Dual-flow path UHPLC/HPLC flexibility accelerates method development and transfer.
• Combined PDA and mass detection enhances selectivity and confidence in impurity identification.
• Automated reporting and custom calculations streamline quality control workflows.
• Single-injection profiling reduces analysis time and sample consumption.

Future Trends and Potential Applications

Wider adoption of dual-flow path chromatography systems and compact mass detectors in routine QA/QC laboratories is anticipated. Advances in software-driven data consolidation will further simplify multi-detector analysis. Emerging technologies may integrate real-time impurity monitoring and automated decision support for rapid regulatory filings and product optimization.

Conclusions

The ACQUITY Arc system coupled with PDA and QDa detection under Empower 3 software offers a robust, single-injection approach for pesticide formulation analysis. The workflow delivers high-efficiency separations, sensitive impurity detection, and rapid structural insights, benefiting product development and quality control.

References

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• Quality Control of Pesticide Products. FAO/IAEA. 2009.
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• Toribo L et al. Chiral separation of triazole pesticides by SFC. J Chrom A. 2004;1046:249–253.
• Waters. ACQUITY Arc System Brochure. 2016.
• Waters. CORTECS 2.7 µm Columns Brochure. 2015.
• Commission Regulation (EU) No 544/2011. 2011.