Acylhydrazone bond dynamic covalent polymer gel monolithic column online coupling to high performance liquid chromatography for analysis of sulfonamides and fluorescent whitening agents in food.
A new dynamic covalent polymer (DCP) gel was well designed and constructed based on imine chemistry. Polycondensation of 4,4' biphenyldicarboxaldehyde and 1,3,5 benzenetricarbohydrazide via Schiff base reaction resulted in an acylhydrazone bond gel (AB gel) DCP. AB gel DCP had three dimensional network of interconnected nanoparticles with hierarchically porous structure. AB gel DCP was successfully fabricated as a monolithic column by an in situ chemical bonding method for online enrichment and separation purpose with excellent permeability. AB gel DCP based monolithic column showed remarkable adsorption affinity towards target analytes including sulfonamides (SAs) and fluorescent whitening agents (FWAs) due to its strong p p affinity, hydrophobic effect and hydrogen bonding interaction. Then, AB gel DCP based monolithic column was applied for online separation and analysis of trace SAs and FWAs in food samples coupled with high performance liquid chromatography (HPLC) Sulfathiazole (ST) and sulfadimidine (SM2) in one positive weever sample were actually found and determined with concentrations of 273.8 and 286.3mg/kg, respectively. 2,5 Bis(5 tert butyl 2 benzoxazolyl) thiophene (FWA184) was actually quantified in one tea infusion sample with the concentration of 268.5ng/L. The spiked experiments suggested the good recoveries in range of 74.5 110% for SAs in weever and shrimp samples with relative standard deviations (RSDs) less than 9.7% and in range of 74.0 113% for FWAs in milk and tea infusion samples with RSDs less than 9.0% AB gel DCP monolithic column was proved to be a promising sample preparation medium for online separation and analysis of trace analytes in food samples with complex matrices.
Journal of chromatography. A