Automating Preparation of Matrix-Matched Standards for Pesticide Residue Analysis Using the Andrew+ Pipetting Robot

Importance of the Topic

Quantitative analysis of pesticide residues in food commodities is essential to ensure consumer safety and regulatory compliance.
One widely adopted strategy to compensate for matrix-induced suppression or enhancement is matrix-matched calibration, where standards are prepared in the same extract as the sample.
This manual preparation is labor-intensive, time-consuming and prone to pipetting errors and repetitive strain injury, creating a demand for automated solutions.

Objectives and Study Overview

This study evaluates the performance of the Andrew+ Pipetting Robot controlled by the cloud-native OneLab Software Platform to automate the preparation of matrix-matched standards for pesticide residue analysis by LC-MS/MS.
Key goals include assessing calibration curve characteristics, time efficiency, precision, accuracy, and traceability compared to manual pipetting.

Methodology and Instrumentation

The automated protocol prepared five concentration levels of 20 representative pesticides in a QuEChERS extract of apples, in duplicate.
Standards were created in water/acetonitrile (9:1) to match initial LC mobile phase conditions.
The Andrew+ Pipetting Robot deck was configured using Domino accessories and electronic pipettes, programmed via OneLab Software to optimize aspiration and dispensing speeds and to apply an air cushion for organic solvents.
Traceability of each pipetting step was recorded as executable scripts.

Main Results and Discussion

Calibration curves were fitted using linear regression with 1/x weighting:

• Automation: average r2 = 0.998
• Manual: average r2 = 0.996

Automated preparation reduced residuals, especially at low concentrations, indicating improved accuracy.
The robotic workflow completed duplicate standard preparation at six levels in under 14 minutes, versus over 35 minutes manually.
Automation minimized human error, improved reproducibility, and freed analysts from repetitive pipetting tasks.

Benefits and Practical Applications

Automating matrix-matched standard preparation offers:

• Significant time savings and higher throughput
• Enhanced precision and accuracy due to consistent pipetting
• Traceable protocols and data provenance through OneLab Software
• Reduced risk of repetitive strain injury for laboratory personnel
• Flexibility to deploy analysts to more value-added tasks

Future Trends and Applications

Further work will focus on validating accuracy and precision across diverse matrices and solvent compositions.
Integration with broader workflow automation and data management platforms could enhance end-to-end traceability.
Cloud-native control and analytics promise improved scalability, remote monitoring, and collaborative method development.

Conclusion

The Andrew+ Pipetting Robot, combined with OneLab Software, delivers automated, accurate, and traceable matrix-matched standard preparation for pesticide residue analysis by LC-MS/MS.
This approach matches or exceeds manual performance while drastically reducing preparation time and human error risk.
Automation thus represents a practical advance for high-throughput laboratories.

References

1. EURL-FV. Validation of MRM Pesticides from the Working Document SANCO/12745/2013 using Three Multiresidue Methods (QuEChERS, Swedish ethyl acetate, and Dutch mini-Luke). 2019.
2. Ross E, Meruva NM, Skinner N. Improving Method Reproducibility and Efficiency in Food Testing: How Can Liquid Handling Automation Help? Waters White Paper 720007332EN. August 2021.
3. Shah D, Wood J, Fujimoto G, McCall E, Hird S, Hancock P. Multiresidue Method for the Quantification of Pesticides in Fruits, Vegetables, Cereals and Black Tea using UPLC-MS/MS. Waters Application Note 720006886EN. February 2021.