On-line preconcentration and determination of sulfadiazine in food samples using surface molecularly imprinted polymer coating by capillary electrophoresis

In this study, on-line preconcentration and selective determination of the trace sulfadiazine (SDZ) exist-ing in milk and hen egg white samples were realized by the capillary electrophoresis using molecularly imprinted polymer (MIP) coated capillary. The capillary coated with MIP was firstly prepared through the surface imprinted techniques, using SDZ as template molecule and dopamine as function monomer and crosslinker, and then amine-terminated poly(2-methyl-2-oxazoline) (PMOXA-NH2) was introduced onto polydopamine layer to reduce the non-specific adsorption. Successful preparation of SDZ-MIP-PMOXA coating was verified by zeta potential, as well as water contact angle. The SDZ-MIP-PMOXA coated cap-illary performed well on-line preconcentration of SDZ and the obtained peak area of SDZ was 46 times higher than that one obtained in bare capillary using the same procedure. Then the proposed on-line pre -concentration method was fully validated and displayed good linear behavior in the concentration from 5.0 to 100.0 ng/mL, with the limit of detection was low to 1.5 ng/mL; and this method presented excel-lent accuracy and robustness. The prepared SDZ-MIP-PMOXA coated capillary also showed high selectivity with the imprinting factor of 5.85 and good repeatability during five consecutive runs with the relative standard deviation value of peak area was 1.6%. At last, the application of the prepared SDZ-MIP-PMOXA coated capillary in the detection of SDZ in spiked food samples was investigated, and good recoveries of 98.7-109.3% were obtained.(c) 2023 Published by Elsevier B.V.

Automated summary

In this study, on-line preconcentration and selective determination of trace sulfadiazine (SDZ) in milk and hen egg white samples were successfully achieved using capillary electrophoresis with molecularly imprinted polymer (MIP) coated capillary. The prepared SDZ-MIP-PMOXA coated capillary showed excellent performance in SDZ preconcentration, with a peak area 46 times higher compared to the bare capillary. The method was fully validated with good linearity, low detection limit, accuracy, and robustness. The SDZ-MIP-PMOXA coating also exhibited high selectivity and repeatability. Additionally, the application of the prepared capillary in detecting SDZ in spiked food samples demonstrated good recoveries.