Multi-Residue Pesticide Analysis in Ginseng Powder: Optimized Cleanup After QuEChERS Extraction for UPLC-MS/MS And GC-MS/MS Analysis

Importance of the Topic

American ginseng powder is a popular herbal supplement with the potential to retain pesticide residues due to its resinous, dried root matrix. Accurate multi‐residue pesticide analysis is critical to ensure consumer safety, regulatory compliance, and quality control in both food and supplement industries. The adaptation of streamlined extraction and cleanup methods for challenging matrices like dried botanicals enhances laboratory throughput and data reliability.

Objectives and Study Overview

This study aimed to develop and validate efficient sample preparation and cleanup protocols for the simultaneous analysis of a broad range of pesticide residues in ginseng powder. Two complementary workflows were evaluated: one based on dispersive solid‐phase extraction (dSPE) coupled to UPLC‐MS/MS, and another using a PSA/carbon SPE cartridge coupled to GC‐MS/MS with atmospheric pressure gas chromatography (APGC). Recovery performance, matrix cleanliness, and instrument maintenance demands were assessed.

Methodology and Instrumentation

Sample Preparation:

• Weighed 2 g of ginseng powder, added 10 mL water, equilibrated for 30 min.
• Added 10 mL acetonitrile and QuEChERS extraction salts; shaken and centrifuged.
• Collected supernatant and split into two aliquots for parallel cleanup.

CLEANUP WORKFLOWS:

• dSPE for UPLC‐MS/MS: 1 mL extract with MgSO₄, PSA, C18, plus graphitized carbon black; centrifuged and diluted for injection.
• SPE for GC‐MS/MS: diluted extract passed through PSA/carbon cartridge topped with MgSO₄; eluate evaporated and reconstituted in toluene.

Instrumentation:

• UPLC‐MS/MS: ACQUITY UPLC I‐Class with BEH C18 column and Xevo TQ‐S operated in ESI positive/negative.
• GC‐MS/MS: Agilent 7890 GC with J&W DB-5MS column, APGC interface on Xevo TQ‐S in positive mode.

Main Results and Discussion

UPLC‐MS/MS recoveries for over 30 pesticides ranged from 84 % to 124 % (RSDs generally <12 %) at 10 and 100 ppb levels, demonstrating robust quantitation across diverse chemistries. GC‐MS/MS with APGC achieved recoveries between 52 % and 122 % (RSDs <15 %) for target analytes, with some lower yields for highly polar compounds. Visual inspection of extracts showed substantial removal of colored co‐extractives after dSPE, protecting the MS source, and SPE cleanup extended GC column and inlet lifetimes, enabling hundreds of injections without maintenance.

Benefits and Practical Applications

• High‐throughput sample preparation with QuEChERS extraction accelerates analysis of dried botanicals.
• Efficient dSPE and SPE cleanups reduce matrix interferences, lowering instrument downtime.
• Single Xevo TQ‐S system converts between LC and GC modes in 30 minutes without venting, maximizing lab flexibility.
• Validates compliance with regulatory limits and ensures product safety in supplement and food sectors.

Future Trends and Potential Applications

Emerging priorities include automation of QuEChERS and cleanup steps, integration with high‐resolution MS for non‐target screening, miniaturization of workflows to reduce solvent use, and standardization of methods across diverse dried botanicals. Expansion to environmental matrices and real‐time monitoring devices may further broaden applications.

Conclusion

The optimized workflows combining QuEChERS extraction with targeted dSPE and SPE cleanups provide a robust, reproducible, and efficient strategy for multi‐residue pesticide analysis in ginseng powder. These methods streamline instrument maintenance, deliver reliable recoveries, and support regulatory compliance in botanical quality control.

References

1. Waters Corporation. Multi‐Residue Pesticide Analysis in Tea: Optimized Cleanup After QuEChERS Extraction for UPLC‐MS/MS and GC‐MS/MS Analysis. Application Note 720004819EN, 2014.