The effects of UiO-66 ultrafine particles on the rapid detection of sulfonamides in milk: Adsorption performance and mechanism

Nanoscale MOFs particles possess both excellent adsorption and dispersion properties. In this study, ultrafine particles UiO-66 (UP/UiO-66) with a particle size below 50 nm were synthesised by a template-controlled method. UP/UiO-66 was able to achieve a maximum adsorption capacity of 139.64 mg/g for 5 methoxylated sulfonamides. Adsorption studies showed that UP/UiO-66 adsorption of sulfonamides can be classified as a pseudo-secondary kinetic adsorption model for single molecular layer adsorption. ELISA (validated by Raman and molecular docking) showed that the sulfonamide molecule was still immunoreactive with antibodies after adsorption by UP/UiO-66. In 15 min, UP/UiO-66 could be used directly in the ELISA test for sulfonamides in milk without elution and separation. The LOQ (IC20) of UP/UiO-66-ELISA for sulfonamides in milk was 0.21-2.05 ng/mL. The ultrafine particle strategy of UiO-66 is expected to be applied to other MOFs and used as a general pretreatment material for residue monitoring in complex matrices.