Electric Field-Assisted Synthesis of Molecularly Imprinted Microelectrode for Triazole Extraction

Xiamen University researchers from Xiamen, China developed a new approach for extracting triazole residues from environmental samples. Their findings were published in the Journal of Chromatography A (1).

Triazoles are a type of azole fungicides commonly used in agriculture and medicine (2). These substances, which include triadimenol (TRN), myclobutanil (MYC), triadimefon (TRF) and hexaconazole (HEX), are valued for their highly antibacterial activity against most fungus. However, they can enter the environment and contaminate water, soil, and food sources. If triazone residuals enter the food chain, they can cause serious adverse consequences to human health, such as cancer, reproductive issues, and blood disorders. To protect consumers, the European Union (EU) Council has regulated triazole maximum residue limits (MRLs) in fruits and vegetables, though this has not been applied to relevant processed products. As such, creating sensitive and reliable methods for monitoring trace triazoles in complex samples, such as fruit juices or environmental waters, is essential.

Composition of fruits and glasses of juice | Image Credit: © BillionPhotos.com - stock.adobe.com

In this study, electric field reinforced solid-phase microextraction (ER-SPME) based on molecularly imprinted microelectrode (MIM) was used for capturing triazoles in environmental water and fruit juice samples prior to high-performance liquid chromatography (HPLC) (3). Various molecularly imprinted adsorbents (MIAs) using triazoles as templates have been used to selectively extract triazoles under SPE and stir bar sorptive extraction (SBSE). However, this process can prove tedious to prepare, all to deal with long extraction durations and unsatisfactory enrichment performance. As such, triadimenol (TRN) and acrylic acid (AA) were used as the template and functional monomer, respectively, to create a new MIM, all whole using a suitable electric field for improving its recognition performance. Afterwards, the new MIM was used as the extraction phase of ER-SPME to specific capture TRN and its structural analogues.

Selective adsorption behaviors and specific capture mechanism under electric field of MIM@ER-SPME towards TRN and its structural analogues were investigated in detail. Deploying the field during MIM synthesis was revealed to favor the formation of uniform and ordered assembly between TRN and AA, leading to the improvement of specific recognition towards TRN and its structural analogues. Additionally, the electric field exerting at the adsorption and desorption steps reinforced its extraction performance while shortening extraction duration. The MIM@ER-SPME presented better extraction efficiencies than that achieved on MIM@SPME (without application of electric field) (a rise of 33.8–62.9%). Adsorption kinetics and isotherm use confirmed that MIM@ER-SPME selectively capturing TRN belonged to chemisorption and single-layer adsorption procedure.

Under beneficial extraction parameters, the approach introduced in this study was successfully used to measure trace triazole residuals in fruit juice and environmental water samples. Further, various merits, such as satisfactory anti-interference ability, superior sensitivity, good regeneration, and high cost-effectiveness and greenness, were found. Overall, the suggested method may prove useful for reliably monitoring trace triazoles in complex samples.

References

(1) Zheng, L.; Wang, L.; Lu, M.; Huang, X. Electric Field-Assisted Synthesis of Molecularly Imprinted Microelectrode for Specific Extraction of Triazoles Before Quantification with HPLC. J. Chromatogr. A 2025, 1748, 465860. DOI: 10.1016/j.chroma.2025.465860

(2) Thrikawala, S.; Mesmar, F.; Bhattacharya, B.; Muhsen, M.; et al. Triazole Fungicides Induce Adipogenesis and Repress Osteoblastogenesis in Zebrafish. Toxicol. Sci. 2023, 193 (2), 119–130. DOI: 10.1093/toxsci/kfad031

(3) Lv, H.; Jin, X.; Zhang, Z.; Chen, Y.; et al. Ultrasound-Assisted Switchable Hydrophilic Solvent-Based Homogeneous Liquid–Liquid Microextraction for the Determination of Triazole Fungicides in Environmental Water by GC-MS. Anal. Methods 2022, 12. DOI: 10.1039/D1AY02109E