This application note describes the use of a quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation approach described in the European Committee (EN) for extraction and cleanup of 17 GC-amenable multiple pesticide class residues in apple. The method involves initial extraction in an aqueous/acetonitrile system, an extraction/partitioning step after the addition of salt, and a cleanup step using dispersive solid phase extraction (dispersive SPE). The two different dispersive SPE cleanup approaches (1 mL and 6 mL aliquot volumes) were evaluated simultaneously after sample extraction. The target pesticides in the apple extracts were then analyzed by gas chromatography/mass spectrometry (GC/MS) operating in selective ion monitoring (SIM) mode. The method was validated in terms of recovery and reproducibility. The limit of quantitation (LOQ) for pesticides in apple is 10 ng/g. This application employed Agilent's Bond Elut QuEChERS kit and produced results well below the maximum residue limits (MRLs) for all the pesticides screened. The spiked levels for the recovery experiments were 10, 50, and 200 ng/g. Recoveries ranged between 68 and 112% (86.0% on average), with RSD below 15% (4.7% on average).
This document describes a validated method for analyzing multiple classes of pesticide residues in apple samples. The procedure utilizes the quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach with specific European Committee (EN) modifications for extraction and cleanup. The study evaluates two different dispersive solid phase extraction (dispersive SPE) cleanup volumes: 1 mL and 6 mL aliquots.
The analysis was performed using an Agilent Gas Chromatograph coupled with an Agilent 5975C Mass Spectrometer operating in selective ion monitoring (SIM) mode. The method targets seventeen GC-amenable pesticides, including organochlorine, organophosphorus, and organonitrogen compounds. Validation results indicate a limit of quantitation (LOQ) of 10 ng/g with average recoveries of 86.0% and relative standard deviations below 4.7%.
| Limit of Quantitation (LOQ) | 10 ng/g |
|---|---|
| Average Recovery Rate | 86.0% |
| Relative Standard Deviation (RSD) | < 4.7% |
| Extraction Solvent | Acetonitrile (ACN) |
| Cleanup Method | Dispersive Solid Phase Extraction (dispersive SPE) |
The limit of quantitation (LOQ) for pesticides in apple is 10 ng/g.
Recoveries ranged between 68% and 112%, with an average of 86.0%. The relative standard deviation (RSD) was below 15%, averaging 4.7%.
The study employed Agilent's Bond Elut QuEChERS kit, specifically the Buffered Extraction kit (p/n 5982-5650) and dispersive SPE kits for General Fruits and Vegetables.