Solar-driven interfacial evaporation has emerged as an innovative and sustainable technology for clean water production. Rational fabrication of monolithic three-dimensional (3D) steam generators has accordingly become a topic of growing...

No abstract

No abstract

Novel haptens were designed and synthesized to prepare antibodies against free histamine, but none resulted in producing suitable antibodies for developing an enzyme-linked immunosorbent assay (ELISA). However, an antiserum was obtained having high specificity and affinity to p-nitrobenzoylated histamine (NPHA), which can be easily formed from reaction between histamine and p-nitrobenzoic acid N-hydroxysuccinimide ester (PNBA-OSu) under mild conditions. Based on rabbit polyclonal antibodies, a competitive indirect ELISA (ciELISA) for histamine determination in foods was developed. After ciELISA and derivatization optimization, the assay showed good sensitivity, with limits of detection of 1.8 mg/kg, 93.6 μg/L, and 93.6 μg/kg in fish, red wine, and yoghurt, respectively, with negligible cross-reactivity with related biogenic amines and amino acids. Average recovery of histamine in fortified food samples ranged from 80.9% to 110.1% with coefficients of variation below 16.3%. Good correlation between the ciELISA and liquid chromatography-tandem mass spectrometry was obtained for spiked food samples.

Histamine (HA) is a biogenic amine that can accumulate to high concentration levels in food as a result of microbial activity and can cause toxic effects in consumers. In this work, a portable electrochemical immunosensor capable of detecting HA with high sensitivity and selectivity was developed. Prussian blue-chitosan-gold nanoparticle (PB-CS-AuNP) nanocomposite films with excellent biocompatibility were synthesized and characterized by scanning electron microscopy and energy dispersive X-ray analysis. The PB-CS-AuNP were coated onto a screen-printed electrode by one-step electrodeposition and used to conjugate the HA ovalbumin conjugate (HA-Ag). HA was determined by a competition between the coating HA-Ag and the HRP labeled HA antibody (HRP-HA-Ab). After careful optimization of assay conditions and Box-Behnken analysis, the developed immunosensor showed a linear range from 0.01 to 100 μg/mL for HA in fish samples. The average recoveries from spiked samples ranged from 97.25% to 105%. The biosensor also showed good specificity, reproducibility, and stability, indicating its potential application in monitoring HA in a simple and low cost manner.