Determination of Pesticides Residues in Food Matrices—An Automated Versus Manual QuEChERS Extraction

The Application Notebook

The Application Notebook, The Application Notebook-06-01-2016, Issue 0

An ever growing area of interest for pesticide residue laboratories is the ability to automate manual steps, particularly in workplaces where they can see as many as 500 samples per day. These analyses typically involves the use of multi-residue methods (both GC–MS-MS and LC–MS-MS), to test for pesticide residues. QuEChERS has proven to be the extraction method of choice for numerous laboratories, due to its ease of use and robustness.

Teledyne Tekmar's AutoMate-Q40 is a robotic system designed to optimize and automate the QuEChERS sample preparation workflow. This revolutionary system automates the following sample extraction requirements: solvent, internal standard and matrix spike addition, vial shaking, vortex mixing, addition of solid reagents (salts, buffers), centrifugation, identifying liquid levels, pipetting, dSPE cleanup, and preserving the final extract.


 

The United States Food and Drug Agency (US FDA) evaluated the extraction performance of the AutoMate-Q40 against the manual process. They compared the automated and manual QuEChERS extraction, using the AOAC 2007.01 unbuffered method. All samples in this evaluation were analyzed using liquid chromatography-tandem mass spectrometry (LC–MS-MS).

Experimental Instrument Conditions

Figure 1 shows the parameters for the QuEChERS extraction procedure for fruits and vegetables using the AutoMate-Q40.


Figure 1: AutoMate-Q40 method parameters.

Results

The scatter plot shows the precision and accuracy recoveries of the 204 pesticides spiked onto the samples of cabbage, valencia oranges, raisins, and purple corn flour. The samples were spiked at 10.0, 50.0, and 250.0 ng/mL. The AutoMate-Q40 system is capable of adding these standards directly to the sample, however in this study; the analyst added the spike directly to the sample manually and allowed 15 min of interaction, before placing inside the AutoMate-Q40.

Acknowledgements

Teledyne Tekmar would like to thank the United States Food and Drug Agency CFSAN Group, namely Kelli A. Simon, James B. Wittenberg, Jon W. Wong, and Alexander J. Krynitsky. Their exceptional work evaluating the system is greatly appreciated.

Teledyne Tekmar
4736 Socialville Foster Rd., Mason, OH 45040
tel. (513) 229-7000
www.teledynetekmar.com