β-cyclodextrin based hydrophilic thin layer molecularly imprinted membrane with di(2-ethylhexyl) phthalate selective removal ability

Sulfonamide-Selective Ambient Mass Spectrometry Ion Source Obtained by Modification of an Iron Sheet with a Hydrophilic Molecularly Imprinted Polymer

We have described a sulfonamide-selective ambient ion source coupled with electrospray ionization mass spectrometry (ESI-MS) for selective extraction and determination of trace sulfonamide antibiotics. It is obtained by modifying an iron sheet with a sulfadiazine-templated hydrophilic molecularly imprinted polymer (SF-HMIP). It behaves as both an online extractor and a MS ion source. Five sulfonamide antibiotics, including sulfamethoxazole (SMZ), sulfamerazine (SMR), sulfisoxazole (SIZ), sulfathiazole (ST), and sulfameter (SMD), were chosen to evaluate SF-HMIP coupled with ESI-MS, which showed good linearity in the range of 0.2-1000 ng/mL with correlation coefficient values (R²) over 0.9946. The limits of detection (LODs) for analysis of pure water and honey were in the range of 0.1-0.2 and 0.2-1.5 ng/mL, respectively. Limits of quantitation (LOQs) for analysis of pure water and honey were in the range of 0.3-0.5 and 1.0-5.0 ng/mL, respectively. The results demonstrated that SF-HMIP combined with ESI-MS could be applied for the direct analysis of five trace sulfonamide compounds in honey and pure water with recoveries ranging from 76 to 129%.

Epitope-imprinted polydopamine electrochemical sensor for ovalbumin detection

A novel, sensitive and selective electrochemical sensor based on epitope-imprinted polydopamine (PDA) was developed for ovalbumin (OVA) detection. Molecularly imprinted polydopamine was synthesized on an AuNP-coated screen-printed carbon electrode (SPCE) via electropolymerization in the presence of OVA IgE-binding epitope as the template. Key process parameters including template concentration, electropolymerization cycle, pH, time required for template removal and rebinding were optimized. Electrochemical detection of OVA was performed by differential pulse voltammetry (DPV) in 5 mM K₃Fe(CN)₆ and 0.1 M KCl as the supporting electrolyte. Under optimized conditions, the sensor demonstrated excellent sensitivity toward OVA with linear range from 23.25 to 232.50 nM (1 to 10 ppm), limit of detection (LOD) of 10.76 nM (0.46 ppm), and limit of quantification (LOQ) of 35.87 nM (1.54 ppm). The sensor also exhibited good selectivity against other proteins such as human serum albumin (HSA), bovine serum albumin (BSA), and lysozyme (LYZ). OVA in wine samples was detected with RSD of 5.63-10.82%, and recovery percentage of 104.74-105.96%. The developed method can be easily adapted to detect other allergic proteins in the food supply chain.