Automated QuEChERS method for high-throughput analysis of pesticides in Cannabis sativa L. flowering tops by GC-MS/MS.

BACKGROUND

QuEChERS extraction is twenty-three years old, but still today continues to expand beyond its most popular application area of pesticide analysis, for instance for contaminants, antibiotics, pharmaceuticals, and drugs testing. With the rise of recent trends in analytical chemistry towards automation and miniaturization, the most arduous challenge remains to move manually practiced QuEChERS procedures to automated workstations.

RESULTS

The present research is focused on the automation and miniaturization of the entire QuEChERS process for the determination of pesticides in Cannabis sativa L. flowering tops. According to the citrate-buffering version of the EN 15662 method, the workflow consisted mainly of two distinct steps: i) citrate-buffered QuEChERS extraction; ii) clean-up by micro dispersive-SPE procedure. Total extraction time was 20 min. The purified extract in acetonitrile was automatically injected into a GC-MS/MS instrument for the rapid screening of forty-five pesticide residues in Cannabis sativa L. flowering tops. According to SANTE/11312/2021v2026 guidelines, linearity, mean recovery, precision as intra- and inter-day repeatability, limit of quantification, and robustness were evaluated. The matrix-matched calibration curves were characterized by satisfactory linearity (≥0.9894) and acceptable individual recoveries, as provided by guidelines. The validated method was used to monitor the presence of pesticides in ten cannabis flowering tops samples.

SIGNIFICANCE: The proposed automated and miniaturized QuEChERS-GC-MS/MS workflow provides a rapid approach for pesticide residue analysis in a complex dried plant matrix, supporting the transfer of conventional manual QuEChERS procedures toward automated, high-throughput analytical platforms, according to White Analytical Chemistry (WAC) principles.