7.3.5. Pesticides

Pesticides are chemical compounds increasingly used in agricultural production, which play an important role in ensuring optimal efficiency and maximizing income. Despite the positive impact on economic aspects, excessive use of pesticides can lead to the production of harmful chemical intermediates in vegetables, fruits and other agricultural products, which is a serious threat to food safety and human health. In order to ensure constant control of the concentration of these substances in agricultural products, it is necessary to find quick methods to confirm the presence and define their concentration [97–102]. Table 7 presents an exemplary fluorescent strategies for pesticides determination with using of QDs.


**Table 7.** QDs-based sensors for pesticides determination.

Kanagasubbulakshmi et al. [99] show the thioglycolic acid (TGA) capped CdTe QDs were highly dispersed and uniform in nature. The TGA surface modification of CdTe did not lead to the agglomeration of QDs. But when an interaction occurred with malathion, the aggregation was formed due to the functional group detachment. The linearity was obtained in the range of 3–21 nM with the LOD 0.68 nM. While Jiménez-López et al. [97] has proposed a multi-commutated flow analysis method for the determination of glyphosate, based on the quenching effect produced by this herbicide on the fluorescence of CdTe quantum dots with the LOD 0.52 <sup>μ</sup>g·mL−1.

Another example of a sensitive direct competitive biomimetic immunosorbent assay method for pesticide detection was proposed by Liu et al. [98], using the hydrophilic imprinted film as artificial antibody and CdSe/ZnS QD label as a marker. A decrease in the fluorescence of the CdSe/ZnS QD conjugate was observed when QDs has attached to the Trichlorfon. Under optimal conditions, the LOD and sensitivity of the biomimetic immunosorbent assay method were found as 9.0 <sup>μ</sup>g·L−<sup>1</sup> and 5.0 mg·L−1.
