QuEChERS Method Proposed to Detect Pesticides in Fruits

Scientists based out of Zhejiang Academy of Agricultural Sciences in Hangzhou, China, recently created a new QuEChERS method for analyzing pesticides in fruit samples, with their work being published in the Journal of Chromatography A (1).

Ripe fruits isolated on white background | Image Credit: © Africa Studio - stock.adobe.com

Pesticides play an important role in protecting foodstuffs, but consuming large amounts can be dangerous. There are many ways to analyze for pesticides, but this study involved the establishment of a new QuEChERS method for the determination of multi-pesticide residues in fruits. While QuEChERS has been widely adopted in this field, current methods involve acetonitrile extraction, separation, and dispersed solid-phase extraction (d-SPE), which can limit preprocessing speeds. This approach involves the use of magnetic nanomaterials, which can be easily separated from extracts under an external magnetic field, enabling quick phase separation without additional waiting time. By improving the sample pre-processing program in this way, the scientists believe this will have great advantages in operation process and reagent dosage, among other factors.

To purify the fruit matrices, the scientists created their own poly-dopamine-modified magnetic nanomaterial (Fe3O4-pDA), which was used as a co-adsorbent with 3-(N, n‑diethyl amino) propyl trimethoxy-silane (PSA) in the developed integrated QuEChERS method to purify the fruit matrix, in addition to absorbing saccharides. This method was used on a variety of fruit samples, with grapes being used as a representative sample. Under optimized conditions, the method showed good linearity for 92.6% of pesticides in the concentration range of 1–150 μg L⁻¹ with method limit of quantitative (mLOQs) ranged from 10 to 18 μg kg⁻¹. From there, tests were conducted on more types of grape and different types of fruit samples, namely apple, watermelon, pear, winter jujube and peach.

Comparison experiments showed that this method, compared to traditional QuEChERS methods, was more convenient to operate, more efficient, and had low reagent consumption. Furthermore, under real sample analysis, the overall detection rate was 52%, with only 2% of samples were exceeding maximum residue limits.

“All results confirmed that the proposed method could be used for the rapid, simple, low-costing and effective analyses of trace multi-pesticides residue in fruit samples,” the scientists wrote in the study (1).

Reference

(1) Qi, P.; Wang, J.; Liu, Z.; Zhao, H.; Wang, Z.; Di, S.; Wang, X. Fabrication of poly-dopamine-modified magnetic nanomaterial and development of integrated QuEChERS method for 122 pesticides residue analysis in fruits. J. Chromatogr. A. 2023, 1708, 464336. DOI: https://doi.org/10.1016/j.chroma.2023.464336